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I have a variable in PHP, and I need its value in my JavaScript code. How can I get my variable from PHP to JavaScript?
I have code that looks like this:
<?php
$val = $myService->getValue(); // Makes an API and database call
On the same page, I have JavaScript code that needs the value of the $val variable to be passed as a parameter:
<script>
myPlugin.start($val); // I tried this, but it didn't work
<?php myPlugin.start($val); ?> // This didn't work either
myPlugin.start(<?=$val?>); // This works sometimes, but sometimes it fails
</script>
There are actually several approaches to do this. Some require more overhead than others, and some are considered better than others.
In no particular order:
Use AJAX to get the data you need from the server.
Echo the data into the page somewhere, and use JavaScript to get the information from the DOM.
Echo the data directly to JavaScript.
In this post, we'll examine each of the above methods, and see the pros and cons of each, as well as how to implement them.
1. Use AJAX to get the data you need from the server
This method is considered the best, because your server side and client side scripts are completely separate.
Pros
Better separation between layers - If tomorrow you stop using PHP, and want to move to a servlet, a REST API, or some other service, you don't have to change much of the JavaScript code.
More readable - JavaScript is JavaScript, PHP is PHP. Without mixing the two, you get more readable code on both languages.
Allows for asynchronous data transfer - Getting the information from PHP might be time/resources expensive. Sometimes you just don't want to wait for the information, load the page, and have the information reach whenever.
Data is not directly found on the markup - This means that your markup is kept clean of any additional data, and only JavaScript sees it.
Cons
Latency - AJAX creates an HTTP request, and HTTP requests are carried over network and have network latencies.
State - Data fetched via a separate HTTP request won't include any information from the HTTP request that fetched the HTML document. You may need this information (e.g., if the HTML document is generated in response to a form submission) and, if you do, will have to transfer it across somehow. If you have ruled out embedding the data in the page (which you have if you are using this technique) then that limits you to cookies/sessions which may be subject to race conditions.
Implementation Example
With AJAX, you need two pages, one is where PHP generates the output, and the second is where JavaScript gets that output:
get-data.php
/* Do some operation here, like talk to the database, the file-session
* The world beyond, limbo, the city of shimmers, and Canada.
*
* AJAX generally uses strings, but you can output JSON, HTML and XML as well.
* It all depends on the Content-type header that you send with your AJAX
* request. */
echo json_encode(42); // In the end, you need to `echo` the result.
// All data should be `json_encode`-d.
// You can `json_encode` any value in PHP, arrays, strings,
// even objects.
index.php (or whatever the actual page is named like)
<!-- snip -->
<script>
fetch("get-data.php")
.then((response) => {
if(!response.ok){ // Before parsing (i.e. decoding) the JSON data,
// check for any errors.
// In case of an error, throw.
throw new Error("Something went wrong!");
}
return response.json(); // Parse the JSON data.
})
.then((data) => {
// This is where you handle what to do with the response.
alert(data); // Will alert: 42
})
.catch((error) => {
// This is where you handle errors.
});
</script>
<!-- snip -->
The above combination of the two files will alert 42 when the file finishes loading.
Some more reading material
Using the Fetch API
How do I return the response from an asynchronous call?
2. Echo the data into the page somewhere, and use JavaScript to get the information from the DOM
This method is less preferable to AJAX, but it still has its advantages. It's still relatively separated between PHP and JavaScript in a sense that there is no PHP directly in the JavaScript.
Pros
Fast - DOM operations are often quick, and you can store and access a lot of data relatively quickly.
Cons
Potentially Unsemantic Markup - Usually, what happens is that you use some sort of <input type=hidden> to store the information, because it's easier to get the information out of inputNode.value, but doing so means that you have a meaningless element in your HTML. HTML has the <meta> element for data about the document, and HTML 5 introduces data-* attributes for data specifically for reading with JavaScript that can be associated with particular elements.
Dirties up the Source - Data that PHP generates is outputted directly to the HTML source, meaning that you get a bigger and less focused HTML source.
Harder to get structured data - Structured data will have to be valid HTML, otherwise you'll have to escape and convert strings yourself.
Tightly couples PHP to your data logic - Because PHP is used in presentation, you can't separate the two cleanly.
Implementation Example
With this, the idea is to create some sort of element which will not be displayed to the user, but is visible to JavaScript.
index.php
<!-- snip -->
<div id="dom-target" style="display: none;">
<?php
$output = "42"; // Again, do some operation, get the output.
echo htmlspecialchars($output); /* You have to escape because the result
will not be valid HTML otherwise. */
?>
</div>
<script>
var div = document.getElementById("dom-target");
var myData = div.textContent;
</script>
<!-- snip -->
3. Echo the data directly to JavaScript
This is probably the easiest to understand.
Pros
Very easily implemented - It takes very little to implement this, and understand.
Does not dirty source - Variables are outputted directly to JavaScript, so the DOM is not affected.
Cons
Tightly couples PHP to your data logic - Because PHP is used in presentation, you can't separate the two cleanly.
Implementation Example
Implementation is relatively straightforward:
<!-- snip -->
<script>
var data = <?php echo json_encode("42", JSON_HEX_TAG); ?>; // Don't forget the extra semicolon!
</script>
<!-- snip -->
Good luck!
I usually use data-* attributes in HTML.
<div
class="service-container"
data-service="<?= htmlspecialchars($myService->getValue()) ?>"
>
</div>
<script>
$(document).ready(function() {
$('.service-container').each(function() {
var container = $(this);
var service = container.data('service');
// Var "service" now contains the value of $myService->getValue();
});
});
</script>
This example uses jQuery, but it can be adapted for another library or vanilla JavaScript.
You can read more about the dataset property here: https://developer.mozilla.org/en-US/docs/Web/API/HTMLElement.dataset
I'm going to try a simpler answer:
Explanation of the problem
First, let's understand the flow of events when a page is served from our server:
First PHP is run, it generates the HTML that is served to the client.
Then, PHP "dies" (i.e. it literally stops running) as that HTML is delivered to the client. I'd like to emphasize that once the code leaves the server, PHP has stopped being part of the page load, and the server has no access access to it anymore.
Then, when the HTML with JavaScript reaches the client, that can then execute the JavaScript on that HTML, provided it is valid Javascript.
So really, the core thing to remember here is that HTTP is stateless. Once a request left the server, the server can not touch it. So, that leaves our options to:
Send more requests from the client after the initial request is done.
Encode what the server had to say in the initial request.
Solutions
That's the core question you should be asking yourself is:
Am I writing a website or an application?
Websites are mainly page based, and the page load times needs to be as fast as possible (for example - Wikipedia). Web applications are more AJAX heavy and perform a lot of round trips to get the client fast information (for example - a stock dashboard).
Website
Sending more requests from the client after the initial request is done is slow as it requires more HTTP requests which have significant overhead. Moreover, it requires asynchronousity as making an AJAX request requires a handler for when it's complete.
I would not recommend making another request unless your site is an application for getting that information from the server.
You want fast response times which have a huge impact on conversion and load times. Making Ajax requests is slow for the initial uptime in this case and unneeded.
You have two ways to tackle the issue
Set a cookie - cookies are headers sent in HTTP requests that both the server and client can read.
Encode the variable as JSON - JSON looks very close to JavaScript objects and most JSON objects are valid JavaScript variables.
Setting a cookie is really not very difficult, you just assign it a value:
setcookie("MyCookie", $value); // Sets the cookie to the value, remember, do not
// Set it with HTTP only to true.
Then, you can read it with JavaScript using document.cookie:
Here is a short hand rolled parser, but the answer I linked to right above this has better tested ones:
var cookies = document.cookie.split(";").
map(function(el){ return el.split("="); }).
reduce(function(prev,cur){ prev[cur[0]] = cur[1]; return prev },{});
alert(cookies["MyCookie"]); // Value set with PHP.
Cookies are good for a little data. This is what tracking services often do.
Once we have more data, we can encode it with JSON inside a JavaScript variable instead:
<script>
var myServerData = <?=json_encode($value)?>; // Don't forget to sanitize
//server data
</script>
Assuming $value is json_encodeable on the PHP side (it usually is). This technique is what Stack Overflow does with its chat for example (only using .NET instead of PHP).
Application
If you're writing an application - suddenly the initial load time isn't always as important as the ongoing performance of the application, and it starts to pay off to load data and code separately.
My answer here explains how to load data using AJAX in JavaScript:
function callback(data){
// What do I do with the response?
}
var httpRequest = new XMLHttpRequest;
httpRequest.onreadystatechange = function(){
if (httpRequest.readyState === 4) { // Request is done
if (httpRequest.status === 200) { // successfully
callback(httpRequest.responseText); // We're calling our method
}
}
};
httpRequest.open('GET', "/echo/json");
httpRequest.send();
Or with jQuery:
$.get("/your/url").done(function(data){
// What do I do with the data?
});
Now, the server just needs to contain a /your/url route/file that contains code that grabs the data and does something with it, in your case:
<?php
$val = myService->getValue(); // Makes an API and database call
header("Content-Type: application/json"); // Advise client of response type
echo json_encode($val); // Write it to the output
This way, our JavaScript file asks for the data and shows it rather than asking for code or for layout. This is cleaner and starts to pay off as the application gets higher. It's also better separation of concerns and it allows testing the client side code without any server side technology involved which is another plus.
Postscript: You have to be very aware of XSS attack vectors when you inject anything from PHP to JavaScript. It's very hard to escape values properly and it's context sensitive. If you're unsure how to deal with XSS, or unaware of it - please read this OWASP article, this one and this question.
<script>
var jsvar = <?php echo json_encode($PHPVar); ?>;
</script>
json_encode() requires:
PHP 5.2.0 or more
$PHPVar encoded as UTF-8, Unicode.
Simply use one of the following methods.
<script type="text/javascript">
var js_variable = '<?php echo $php_variable;?>';
<script>
OR
<script type="text/javascript">
var js_variable = <?php echo json_encode($php_variable); ?>;
</script>
I quite like the way the WordPress works with its enqueue and localize functions, so following that model, I wrote a simple class for putting a scripts into page according to the script dependencies, and for making additional data available for the script.
class mHeader {
private $scripts = array();
/**
* #param string $id Unique script identifier
* #param string $src Script src attribute
* #param array $deps An array of dependencies ( script identifiers ).
* #param array $data An array, data that will be json_encoded and available to the script.
*/
function enqueue_script($id, $src, $deps = array(), $data = array()) {
$this->scripts[$id] = array('src' => $src, 'deps' => $deps, 'data' => $data);
}
private function dependencies($script) {
if ($script['deps']) {
return array_map(array($this, 'dependencies'), array_intersect_key($this->scripts, array_flip($script['deps'])));
}
}
private function _unset($key, &$deps, &$out) {
$out[$key] = $this->scripts[$key];
unset($deps[$key]);
}
private function flattern(&$deps, &$out = array()) {
foreach($deps as $key => $value) {
empty($value) ? $this->_unset($key, $deps, $out) : $this->flattern( $deps[$key], $out);
}
}
function print_scripts() {
if (!$this->scripts)
return;
$deps = array_map(array($this, 'dependencies'), $this->scripts);
while ($deps)
$this->flattern($deps, $js);
foreach($js as $key => $script) {
$script['data'] && printf("<script> var %s = %s; </script>" . PHP_EOL, key($script['data']), json_encode(current( $script['data'])));
echo "<script id=\"$key-js\" src=\"$script[src]\" type=\"text/javascript\"></script>" . PHP_EOL;
}
}
}
The call to the enqueue_script() function is for adding script, setting the source and dependencies on other scripts, and additional data needed for the script.
$header = new mHeader();
$header->enqueue_script('jquery-ui', '//ajax.googleapis.com/ajax/libs/jqueryui/1.10.4/jquery-ui.min.js', array('jquery'));
$header->enqueue_script('jquery', '//ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js');
$header->enqueue_script('custom-script', '//custom-script.min.js', array('jquery-ui'), array('mydata' => array('value' => 20)));
$header->print_scripts();
And, print_scripts() method of the above example will send this output:
<script id="jquery-js" src="//ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js" type="text/javascript"></script>
<script id="jquery-ui-js" src="//ajax.googleapis.com/ajax/libs/jqueryui/1.10.4/jquery-ui.min.js" type="text/javascript"></script>
<script> var mydata = {"value":20}; </script>
<script id="custom-script-js" src="//custom-script.min.js" type="text/javascript"></script>
Regardless the fact that the script 'jquery' is enqueued after the 'jquery-ui', it is printed before because it is defined in 'jquery-ui' that it depends on 'jquery'.
Additional data for the 'custom-script' are inside a new script block and are placed in front of it, it contains mydata object that holds additional data, now available to 'custom-script'.
Try this:
<?php
echo "<script> var x = " . json_encode($phpVariable) . "</script>";
?>
--
-After trying this for a while
Although it works, however it slows down the performance. As PHP is a server-side script while JavaScript is a user side.
I have come out with an easy method to assign JavaScript variables using PHP.
It uses HTML5 data attributes to store PHP variables and then it's assigned to JavaScript on page load.
Example:
<?php
$variable_1 = "QNimate";
$variable_2 = "QScutter";
?>
<span id="storage" data-variable-one="<?php echo $variable_1; ?>" data-variable-two="<?php echo $variable_2; ?>"></span>
<?php
Here is the JavaScript code
var variable_1 = undefined;
var variable_2 = undefined;
window.onload = function(){
variable_1 = document.getElementById("storage").getAttribute("data-variable-one");
variable_2 = document.getElementById("storage").getAttribute("data-variable-two");
}
Convert the data into JSON
Call AJAX to recieve JSON file
Convert JSON into Javascript object
Example:
STEP 1
<?php
$servername = "localhost";
$username = "";
$password = "";
$dbname = "";
$conn = new mysqli($servername, $username, $password, $dbname);
if ($conn->connect_error) {
die("Connection failed: " . $conn->connect_error);
}
$sql = "SELECT id, name, image FROM phone";
$result = $conn->query($sql);
while($row = $result->fetch_assoc()){
$v[] = $row;
}
echo json_encode($v);
$conn->close();
?>
STEP 2
function showUser(fnc) {
var xhttp = new XMLHttpRequest();
xhttp.onreadystatechange = function() {
if (this.readyState == 4 && this.status == 200) {
// STEP 3
var p = JSON.parse(this.responseText);
}
}
}
myPlugin.start($val); // Tried this, didn't work
It doesn't work because $val is undefined as far as JavaScript is concerned, i.e. the PHP code did not output anything for $val. Try viewing the source in your browser and here is what you'll see:
myPlugin.start(); // I tried this, and it didn't work
And
<?php myPlugin.start($val); ?> // This didn't work either
This doesn't work because PHP will try to treat myPlugin as a constant and when that fails it will try to treat it as the string 'myPlugin' which it will try to concatenate with the output of the PHP function start() and since that is undefined it will produce a fatal error.
And
myPlugin.start(<?=$val?> // This works sometimes, but sometimes it fails
While this is most likely to work, since the PHP code is producing valid JavaScript with the expected arguments, if it fails, chances are it's because myPlugin isn't ready yet. Check your order of execution.
Also you should note that the PHP code output is insecure and should be filtered with json_encode().
EDIT
Because I didn't notice the missing parenthesis in myPlugin.start(<?=$val?> :-\
As #Second Rikudo points out, for it to work correctly $val would need to contain the closing parenthesis, for example: $val="42);"
Meaning that the PHP will now produce myPlugin.start(42); and will work as expected when executed by the JavaScript code.
Here is is the trick:
Here is your 'PHP' to use that variable:
<?php
$name = 'PHP variable';
echo '<script>';
echo 'var name = ' . json_encode($name) . ';';
echo '</script>';
?>
Now you have a JavaScript variable called 'name', and here is your JavaScript code to use that variable:
<script>
console.log("I am everywhere " + name);
</script>
Let's say your variable is always integer. In that case this is easier:
<?PHP
$number = 4;
echo '<script>';
echo 'var number = ' . $number . ';';
echo 'alert(number);';
echo '</script>';
?>
Output:
<script>var number = 4;alert(number);</script>
Let's say your variable is not an integer, but if you try above method you will get something like this:
<script>var number = abcd;alert(number);</script>
But in JavaScript this is a syntax error.
So in PHP we have a function call json_encode that encode string to a JSON object.
<?PHP
$number = 'abcd';
echo '<script>';
echo 'var number = ' . json_encode($number) . ';';
echo 'alert(number);';
echo '</script>';
?>
Since abcd in JSON is "abcd", it looks like this:
<script>var number = "abcd";alert(number);</script>
You can use same method for arrays:
<?PHP
$details = [
'name' => 'supun',
'age' => 456,
'weight' => '55'
];
echo '<script>';
echo 'var details = ' . json_encode($details) . ';';
echo 'alert(details);';
echo 'console.log(details);';
echo '</script>';
?>
And your JavaScript code looks like this:
<script>var details = {"name":"supun","age":456,"weight":"55"};alert(details);console.log(details);</script>
Console output
I'll assume that the data to transmit is a string.
As other commenters have stated, AJAX is one possible solution, but the cons outweigh the pros: it has a latency and it is harder to program (it needs the code to retrieve the value both server- and client-side), when a simpler escaping function should suffice.
So, we're back to escaping. json_encode($string) works if you encode the source string as UTF-8 first in case it is not already, because json_encode requires UTF-8 data. If the string is in ISO-8859-1 then you can simply use json_encode(utf8_encode($string)); otherwise you can always use iconv to do the conversion first.
But there's a big gotcha. If you're using it in events, you need to run htmlspecialchars() on the result in order to make it correct code. And then you have to either be careful to use double quotes to enclose the event, or always add ENT_QUOTES to htmlspecialchars. For example:
<?php
$myvar = "I'm in \"UTF-8\" encoding and I have <script>script tags</script> & ampersand!";
// Fails:
//echo '<body onload="alert(', json_encode($myvar), ');">';
// Fails:
//echo "<body onload='alert(", json_encode($myvar), ");'>";
// Fails:
//echo "<body onload='alert(", htmlspecialchars(json_encode($myvar)), ");'>";
// Works:
//echo "<body onload='alert(", htmlspecialchars(json_encode($myvar), ENT_QUOTES), ");'>";
// Works:
echo '<body onload="alert(', htmlspecialchars(json_encode($myvar)), ');">';
echo "</body>";
However, you can't use htmlspecialchars on regular JavaScript code (code enclosed in <script>...</script> tags). That makes use of this function prone to mistakes, by forgetting to htmlspecialchars the result when writing event code.
It's possible to write a function that does not have that problem, and can be used both in events and in regular JavaScript code, as long as you enclose your events always in single quotes, or always in double quotes. Here is my proposal, requiring them to be in double quotes (which I prefer):
<?php
// Optionally pass the encoding of the source string, if not UTF-8
function escapeJSString($string, $encoding = 'UTF-8')
{
if ($encoding != 'UTF-8')
$string = iconv($encoding, 'UTF-8', $string);
$flags = JSON_HEX_TAG|JSON_HEX_AMP|JSON_HEX_APOS|JSON_HEX_QUOT|JSON_UNESCAPED_SLASHES;
$string = substr(json_encode($string, $flags), 1, -1);
return "'$string'";
}
The function requires PHP 5.4+. Example usage:
<?php
$myvar = "I'm in \"UTF-8\" encoding and I have <script>script tags</script> & ampersand!";
// Note use of double quotes to enclose the event definition!
echo '<body onload="alert(', escapeJSString($myvar), ');">';
// Example with regular code:
echo '<script>alert(', escapeJSString($myvar), ');</script>';
echo '</body>';
After much research, I found the easiest method is to pass all kinds of variables easily.
In the server script, you have two variables, and you are trying to send them to the client scripts:
$php_var1 ="Hello world";
$php_var2 ="Helloow";
echo '<script>';
echo 'var js_variable1= ' . json_encode($php_var1) . ';';
echo 'var js_variable2= ' . json_encode($php_var2) . ';';
echo '</script>';
In any of your JavaScript code called on the page, simply call those variables.
PHP
$fruits = array("apple" => "yellow", "strawberry" => "red", "kiwi" => "green");
<script>
var color = <?php echo json_encode($fruits) ?>;
</script>
<script src="../yourexternal.js"></script>
JS (yourexternal.js)
alert("The apple color is" + color['apple'] + ", the strawberry color is " + color['strawberry'] + " and the kiwi color is " + color['kiwi'] + ".");
OUTPUT
The apple color is yellow, the strawberry color is red and the kiwi
color is green.
This is what works for me in 2022, I used this solution to get the email of the current user
I create a shortcode using PHP and added it to PHP .function:
function my_get_current_user_email(){
$current_user = wp_get_current_user();
$email = $current_user->user_email;
return $email;
}
add_shortcode( 'get_email', 'my_get_current_user_email');
Then use a div to wrap the shortcode:
<div id="target-content" style="display: none;">
[get_email]
</div>
Finally, access the content of the Div with JavaScript:
const databox = document.getElementById("target-content");
const dataContent = databox.textContent;
console.log(dataContent)
This work perfectly for what I wanted and I hope it will work for you too.
As per your code
<$php
$val = $myService->getValue(); // Makes an API and database call
echo '<span id="value">'.$val.'</span>';
$>
Now you can get value using DOM, use innerHTML of span id, in this case you don't need to do any call to server, or Ajax or another thing.
Your page will print it using PHP, and you JavaScript will get value using DOM.
<?php
$val = $myService->getValue(); // Makes an API and database call
echo "
<script>
myPlugin.start({$val});
</script> ";
?>
we can do it using php heredoc:
<?php
$inPhpVar = "i am php var";
$ScriptInline = <<<JS
<script>
alert('{$inPhpVar} that used in js code');
</script>
JS;
echo $ScriptInline;
?>
Want to improve this post? Provide detailed answers to this question, including citations and an explanation of why your answer is correct. Answers without enough detail may be edited or deleted.
I have a variable in PHP, and I need its value in my JavaScript code. How can I get my variable from PHP to JavaScript?
I have code that looks like this:
<?php
$val = $myService->getValue(); // Makes an API and database call
On the same page, I have JavaScript code that needs the value of the $val variable to be passed as a parameter:
<script>
myPlugin.start($val); // I tried this, but it didn't work
<?php myPlugin.start($val); ?> // This didn't work either
myPlugin.start(<?=$val?>); // This works sometimes, but sometimes it fails
</script>
There are actually several approaches to do this. Some require more overhead than others, and some are considered better than others.
In no particular order:
Use AJAX to get the data you need from the server.
Echo the data into the page somewhere, and use JavaScript to get the information from the DOM.
Echo the data directly to JavaScript.
In this post, we'll examine each of the above methods, and see the pros and cons of each, as well as how to implement them.
1. Use AJAX to get the data you need from the server
This method is considered the best, because your server side and client side scripts are completely separate.
Pros
Better separation between layers - If tomorrow you stop using PHP, and want to move to a servlet, a REST API, or some other service, you don't have to change much of the JavaScript code.
More readable - JavaScript is JavaScript, PHP is PHP. Without mixing the two, you get more readable code on both languages.
Allows for asynchronous data transfer - Getting the information from PHP might be time/resources expensive. Sometimes you just don't want to wait for the information, load the page, and have the information reach whenever.
Data is not directly found on the markup - This means that your markup is kept clean of any additional data, and only JavaScript sees it.
Cons
Latency - AJAX creates an HTTP request, and HTTP requests are carried over network and have network latencies.
State - Data fetched via a separate HTTP request won't include any information from the HTTP request that fetched the HTML document. You may need this information (e.g., if the HTML document is generated in response to a form submission) and, if you do, will have to transfer it across somehow. If you have ruled out embedding the data in the page (which you have if you are using this technique) then that limits you to cookies/sessions which may be subject to race conditions.
Implementation Example
With AJAX, you need two pages, one is where PHP generates the output, and the second is where JavaScript gets that output:
get-data.php
/* Do some operation here, like talk to the database, the file-session
* The world beyond, limbo, the city of shimmers, and Canada.
*
* AJAX generally uses strings, but you can output JSON, HTML and XML as well.
* It all depends on the Content-type header that you send with your AJAX
* request. */
echo json_encode(42); // In the end, you need to `echo` the result.
// All data should be `json_encode`-d.
// You can `json_encode` any value in PHP, arrays, strings,
// even objects.
index.php (or whatever the actual page is named like)
<!-- snip -->
<script>
fetch("get-data.php")
.then((response) => {
if(!response.ok){ // Before parsing (i.e. decoding) the JSON data,
// check for any errors.
// In case of an error, throw.
throw new Error("Something went wrong!");
}
return response.json(); // Parse the JSON data.
})
.then((data) => {
// This is where you handle what to do with the response.
alert(data); // Will alert: 42
})
.catch((error) => {
// This is where you handle errors.
});
</script>
<!-- snip -->
The above combination of the two files will alert 42 when the file finishes loading.
Some more reading material
Using the Fetch API
How do I return the response from an asynchronous call?
2. Echo the data into the page somewhere, and use JavaScript to get the information from the DOM
This method is less preferable to AJAX, but it still has its advantages. It's still relatively separated between PHP and JavaScript in a sense that there is no PHP directly in the JavaScript.
Pros
Fast - DOM operations are often quick, and you can store and access a lot of data relatively quickly.
Cons
Potentially Unsemantic Markup - Usually, what happens is that you use some sort of <input type=hidden> to store the information, because it's easier to get the information out of inputNode.value, but doing so means that you have a meaningless element in your HTML. HTML has the <meta> element for data about the document, and HTML 5 introduces data-* attributes for data specifically for reading with JavaScript that can be associated with particular elements.
Dirties up the Source - Data that PHP generates is outputted directly to the HTML source, meaning that you get a bigger and less focused HTML source.
Harder to get structured data - Structured data will have to be valid HTML, otherwise you'll have to escape and convert strings yourself.
Tightly couples PHP to your data logic - Because PHP is used in presentation, you can't separate the two cleanly.
Implementation Example
With this, the idea is to create some sort of element which will not be displayed to the user, but is visible to JavaScript.
index.php
<!-- snip -->
<div id="dom-target" style="display: none;">
<?php
$output = "42"; // Again, do some operation, get the output.
echo htmlspecialchars($output); /* You have to escape because the result
will not be valid HTML otherwise. */
?>
</div>
<script>
var div = document.getElementById("dom-target");
var myData = div.textContent;
</script>
<!-- snip -->
3. Echo the data directly to JavaScript
This is probably the easiest to understand.
Pros
Very easily implemented - It takes very little to implement this, and understand.
Does not dirty source - Variables are outputted directly to JavaScript, so the DOM is not affected.
Cons
Tightly couples PHP to your data logic - Because PHP is used in presentation, you can't separate the two cleanly.
Implementation Example
Implementation is relatively straightforward:
<!-- snip -->
<script>
var data = <?php echo json_encode("42", JSON_HEX_TAG); ?>; // Don't forget the extra semicolon!
</script>
<!-- snip -->
Good luck!
I usually use data-* attributes in HTML.
<div
class="service-container"
data-service="<?= htmlspecialchars($myService->getValue()) ?>"
>
</div>
<script>
$(document).ready(function() {
$('.service-container').each(function() {
var container = $(this);
var service = container.data('service');
// Var "service" now contains the value of $myService->getValue();
});
});
</script>
This example uses jQuery, but it can be adapted for another library or vanilla JavaScript.
You can read more about the dataset property here: https://developer.mozilla.org/en-US/docs/Web/API/HTMLElement.dataset
I'm going to try a simpler answer:
Explanation of the problem
First, let's understand the flow of events when a page is served from our server:
First PHP is run, it generates the HTML that is served to the client.
Then, PHP "dies" (i.e. it literally stops running) as that HTML is delivered to the client. I'd like to emphasize that once the code leaves the server, PHP has stopped being part of the page load, and the server has no access access to it anymore.
Then, when the HTML with JavaScript reaches the client, that can then execute the JavaScript on that HTML, provided it is valid Javascript.
So really, the core thing to remember here is that HTTP is stateless. Once a request left the server, the server can not touch it. So, that leaves our options to:
Send more requests from the client after the initial request is done.
Encode what the server had to say in the initial request.
Solutions
That's the core question you should be asking yourself is:
Am I writing a website or an application?
Websites are mainly page based, and the page load times needs to be as fast as possible (for example - Wikipedia). Web applications are more AJAX heavy and perform a lot of round trips to get the client fast information (for example - a stock dashboard).
Website
Sending more requests from the client after the initial request is done is slow as it requires more HTTP requests which have significant overhead. Moreover, it requires asynchronousity as making an AJAX request requires a handler for when it's complete.
I would not recommend making another request unless your site is an application for getting that information from the server.
You want fast response times which have a huge impact on conversion and load times. Making Ajax requests is slow for the initial uptime in this case and unneeded.
You have two ways to tackle the issue
Set a cookie - cookies are headers sent in HTTP requests that both the server and client can read.
Encode the variable as JSON - JSON looks very close to JavaScript objects and most JSON objects are valid JavaScript variables.
Setting a cookie is really not very difficult, you just assign it a value:
setcookie("MyCookie", $value); // Sets the cookie to the value, remember, do not
// Set it with HTTP only to true.
Then, you can read it with JavaScript using document.cookie:
Here is a short hand rolled parser, but the answer I linked to right above this has better tested ones:
var cookies = document.cookie.split(";").
map(function(el){ return el.split("="); }).
reduce(function(prev,cur){ prev[cur[0]] = cur[1]; return prev },{});
alert(cookies["MyCookie"]); // Value set with PHP.
Cookies are good for a little data. This is what tracking services often do.
Once we have more data, we can encode it with JSON inside a JavaScript variable instead:
<script>
var myServerData = <?=json_encode($value)?>; // Don't forget to sanitize
//server data
</script>
Assuming $value is json_encodeable on the PHP side (it usually is). This technique is what Stack Overflow does with its chat for example (only using .NET instead of PHP).
Application
If you're writing an application - suddenly the initial load time isn't always as important as the ongoing performance of the application, and it starts to pay off to load data and code separately.
My answer here explains how to load data using AJAX in JavaScript:
function callback(data){
// What do I do with the response?
}
var httpRequest = new XMLHttpRequest;
httpRequest.onreadystatechange = function(){
if (httpRequest.readyState === 4) { // Request is done
if (httpRequest.status === 200) { // successfully
callback(httpRequest.responseText); // We're calling our method
}
}
};
httpRequest.open('GET', "/echo/json");
httpRequest.send();
Or with jQuery:
$.get("/your/url").done(function(data){
// What do I do with the data?
});
Now, the server just needs to contain a /your/url route/file that contains code that grabs the data and does something with it, in your case:
<?php
$val = myService->getValue(); // Makes an API and database call
header("Content-Type: application/json"); // Advise client of response type
echo json_encode($val); // Write it to the output
This way, our JavaScript file asks for the data and shows it rather than asking for code or for layout. This is cleaner and starts to pay off as the application gets higher. It's also better separation of concerns and it allows testing the client side code without any server side technology involved which is another plus.
Postscript: You have to be very aware of XSS attack vectors when you inject anything from PHP to JavaScript. It's very hard to escape values properly and it's context sensitive. If you're unsure how to deal with XSS, or unaware of it - please read this OWASP article, this one and this question.
<script>
var jsvar = <?php echo json_encode($PHPVar); ?>;
</script>
json_encode() requires:
PHP 5.2.0 or more
$PHPVar encoded as UTF-8, Unicode.
Simply use one of the following methods.
<script type="text/javascript">
var js_variable = '<?php echo $php_variable;?>';
<script>
OR
<script type="text/javascript">
var js_variable = <?php echo json_encode($php_variable); ?>;
</script>
I quite like the way the WordPress works with its enqueue and localize functions, so following that model, I wrote a simple class for putting a scripts into page according to the script dependencies, and for making additional data available for the script.
class mHeader {
private $scripts = array();
/**
* #param string $id Unique script identifier
* #param string $src Script src attribute
* #param array $deps An array of dependencies ( script identifiers ).
* #param array $data An array, data that will be json_encoded and available to the script.
*/
function enqueue_script($id, $src, $deps = array(), $data = array()) {
$this->scripts[$id] = array('src' => $src, 'deps' => $deps, 'data' => $data);
}
private function dependencies($script) {
if ($script['deps']) {
return array_map(array($this, 'dependencies'), array_intersect_key($this->scripts, array_flip($script['deps'])));
}
}
private function _unset($key, &$deps, &$out) {
$out[$key] = $this->scripts[$key];
unset($deps[$key]);
}
private function flattern(&$deps, &$out = array()) {
foreach($deps as $key => $value) {
empty($value) ? $this->_unset($key, $deps, $out) : $this->flattern( $deps[$key], $out);
}
}
function print_scripts() {
if (!$this->scripts)
return;
$deps = array_map(array($this, 'dependencies'), $this->scripts);
while ($deps)
$this->flattern($deps, $js);
foreach($js as $key => $script) {
$script['data'] && printf("<script> var %s = %s; </script>" . PHP_EOL, key($script['data']), json_encode(current( $script['data'])));
echo "<script id=\"$key-js\" src=\"$script[src]\" type=\"text/javascript\"></script>" . PHP_EOL;
}
}
}
The call to the enqueue_script() function is for adding script, setting the source and dependencies on other scripts, and additional data needed for the script.
$header = new mHeader();
$header->enqueue_script('jquery-ui', '//ajax.googleapis.com/ajax/libs/jqueryui/1.10.4/jquery-ui.min.js', array('jquery'));
$header->enqueue_script('jquery', '//ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js');
$header->enqueue_script('custom-script', '//custom-script.min.js', array('jquery-ui'), array('mydata' => array('value' => 20)));
$header->print_scripts();
And, print_scripts() method of the above example will send this output:
<script id="jquery-js" src="//ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js" type="text/javascript"></script>
<script id="jquery-ui-js" src="//ajax.googleapis.com/ajax/libs/jqueryui/1.10.4/jquery-ui.min.js" type="text/javascript"></script>
<script> var mydata = {"value":20}; </script>
<script id="custom-script-js" src="//custom-script.min.js" type="text/javascript"></script>
Regardless the fact that the script 'jquery' is enqueued after the 'jquery-ui', it is printed before because it is defined in 'jquery-ui' that it depends on 'jquery'.
Additional data for the 'custom-script' are inside a new script block and are placed in front of it, it contains mydata object that holds additional data, now available to 'custom-script'.
Try this:
<?php
echo "<script> var x = " . json_encode($phpVariable) . "</script>";
?>
--
-After trying this for a while
Although it works, however it slows down the performance. As PHP is a server-side script while JavaScript is a user side.
I have come out with an easy method to assign JavaScript variables using PHP.
It uses HTML5 data attributes to store PHP variables and then it's assigned to JavaScript on page load.
Example:
<?php
$variable_1 = "QNimate";
$variable_2 = "QScutter";
?>
<span id="storage" data-variable-one="<?php echo $variable_1; ?>" data-variable-two="<?php echo $variable_2; ?>"></span>
<?php
Here is the JavaScript code
var variable_1 = undefined;
var variable_2 = undefined;
window.onload = function(){
variable_1 = document.getElementById("storage").getAttribute("data-variable-one");
variable_2 = document.getElementById("storage").getAttribute("data-variable-two");
}
Convert the data into JSON
Call AJAX to recieve JSON file
Convert JSON into Javascript object
Example:
STEP 1
<?php
$servername = "localhost";
$username = "";
$password = "";
$dbname = "";
$conn = new mysqli($servername, $username, $password, $dbname);
if ($conn->connect_error) {
die("Connection failed: " . $conn->connect_error);
}
$sql = "SELECT id, name, image FROM phone";
$result = $conn->query($sql);
while($row = $result->fetch_assoc()){
$v[] = $row;
}
echo json_encode($v);
$conn->close();
?>
STEP 2
function showUser(fnc) {
var xhttp = new XMLHttpRequest();
xhttp.onreadystatechange = function() {
if (this.readyState == 4 && this.status == 200) {
// STEP 3
var p = JSON.parse(this.responseText);
}
}
}
myPlugin.start($val); // Tried this, didn't work
It doesn't work because $val is undefined as far as JavaScript is concerned, i.e. the PHP code did not output anything for $val. Try viewing the source in your browser and here is what you'll see:
myPlugin.start(); // I tried this, and it didn't work
And
<?php myPlugin.start($val); ?> // This didn't work either
This doesn't work because PHP will try to treat myPlugin as a constant and when that fails it will try to treat it as the string 'myPlugin' which it will try to concatenate with the output of the PHP function start() and since that is undefined it will produce a fatal error.
And
myPlugin.start(<?=$val?> // This works sometimes, but sometimes it fails
While this is most likely to work, since the PHP code is producing valid JavaScript with the expected arguments, if it fails, chances are it's because myPlugin isn't ready yet. Check your order of execution.
Also you should note that the PHP code output is insecure and should be filtered with json_encode().
EDIT
Because I didn't notice the missing parenthesis in myPlugin.start(<?=$val?> :-\
As #Second Rikudo points out, for it to work correctly $val would need to contain the closing parenthesis, for example: $val="42);"
Meaning that the PHP will now produce myPlugin.start(42); and will work as expected when executed by the JavaScript code.
Here is is the trick:
Here is your 'PHP' to use that variable:
<?php
$name = 'PHP variable';
echo '<script>';
echo 'var name = ' . json_encode($name) . ';';
echo '</script>';
?>
Now you have a JavaScript variable called 'name', and here is your JavaScript code to use that variable:
<script>
console.log("I am everywhere " + name);
</script>
Let's say your variable is always integer. In that case this is easier:
<?PHP
$number = 4;
echo '<script>';
echo 'var number = ' . $number . ';';
echo 'alert(number);';
echo '</script>';
?>
Output:
<script>var number = 4;alert(number);</script>
Let's say your variable is not an integer, but if you try above method you will get something like this:
<script>var number = abcd;alert(number);</script>
But in JavaScript this is a syntax error.
So in PHP we have a function call json_encode that encode string to a JSON object.
<?PHP
$number = 'abcd';
echo '<script>';
echo 'var number = ' . json_encode($number) . ';';
echo 'alert(number);';
echo '</script>';
?>
Since abcd in JSON is "abcd", it looks like this:
<script>var number = "abcd";alert(number);</script>
You can use same method for arrays:
<?PHP
$details = [
'name' => 'supun',
'age' => 456,
'weight' => '55'
];
echo '<script>';
echo 'var details = ' . json_encode($details) . ';';
echo 'alert(details);';
echo 'console.log(details);';
echo '</script>';
?>
And your JavaScript code looks like this:
<script>var details = {"name":"supun","age":456,"weight":"55"};alert(details);console.log(details);</script>
Console output
I'll assume that the data to transmit is a string.
As other commenters have stated, AJAX is one possible solution, but the cons outweigh the pros: it has a latency and it is harder to program (it needs the code to retrieve the value both server- and client-side), when a simpler escaping function should suffice.
So, we're back to escaping. json_encode($string) works if you encode the source string as UTF-8 first in case it is not already, because json_encode requires UTF-8 data. If the string is in ISO-8859-1 then you can simply use json_encode(utf8_encode($string)); otherwise you can always use iconv to do the conversion first.
But there's a big gotcha. If you're using it in events, you need to run htmlspecialchars() on the result in order to make it correct code. And then you have to either be careful to use double quotes to enclose the event, or always add ENT_QUOTES to htmlspecialchars. For example:
<?php
$myvar = "I'm in \"UTF-8\" encoding and I have <script>script tags</script> & ampersand!";
// Fails:
//echo '<body onload="alert(', json_encode($myvar), ');">';
// Fails:
//echo "<body onload='alert(", json_encode($myvar), ");'>";
// Fails:
//echo "<body onload='alert(", htmlspecialchars(json_encode($myvar)), ");'>";
// Works:
//echo "<body onload='alert(", htmlspecialchars(json_encode($myvar), ENT_QUOTES), ");'>";
// Works:
echo '<body onload="alert(', htmlspecialchars(json_encode($myvar)), ');">';
echo "</body>";
However, you can't use htmlspecialchars on regular JavaScript code (code enclosed in <script>...</script> tags). That makes use of this function prone to mistakes, by forgetting to htmlspecialchars the result when writing event code.
It's possible to write a function that does not have that problem, and can be used both in events and in regular JavaScript code, as long as you enclose your events always in single quotes, or always in double quotes. Here is my proposal, requiring them to be in double quotes (which I prefer):
<?php
// Optionally pass the encoding of the source string, if not UTF-8
function escapeJSString($string, $encoding = 'UTF-8')
{
if ($encoding != 'UTF-8')
$string = iconv($encoding, 'UTF-8', $string);
$flags = JSON_HEX_TAG|JSON_HEX_AMP|JSON_HEX_APOS|JSON_HEX_QUOT|JSON_UNESCAPED_SLASHES;
$string = substr(json_encode($string, $flags), 1, -1);
return "'$string'";
}
The function requires PHP 5.4+. Example usage:
<?php
$myvar = "I'm in \"UTF-8\" encoding and I have <script>script tags</script> & ampersand!";
// Note use of double quotes to enclose the event definition!
echo '<body onload="alert(', escapeJSString($myvar), ');">';
// Example with regular code:
echo '<script>alert(', escapeJSString($myvar), ');</script>';
echo '</body>';
After much research, I found the easiest method is to pass all kinds of variables easily.
In the server script, you have two variables, and you are trying to send them to the client scripts:
$php_var1 ="Hello world";
$php_var2 ="Helloow";
echo '<script>';
echo 'var js_variable1= ' . json_encode($php_var1) . ';';
echo 'var js_variable2= ' . json_encode($php_var2) . ';';
echo '</script>';
In any of your JavaScript code called on the page, simply call those variables.
PHP
$fruits = array("apple" => "yellow", "strawberry" => "red", "kiwi" => "green");
<script>
var color = <?php echo json_encode($fruits) ?>;
</script>
<script src="../yourexternal.js"></script>
JS (yourexternal.js)
alert("The apple color is" + color['apple'] + ", the strawberry color is " + color['strawberry'] + " and the kiwi color is " + color['kiwi'] + ".");
OUTPUT
The apple color is yellow, the strawberry color is red and the kiwi
color is green.
This is what works for me in 2022, I used this solution to get the email of the current user
I create a shortcode using PHP and added it to PHP .function:
function my_get_current_user_email(){
$current_user = wp_get_current_user();
$email = $current_user->user_email;
return $email;
}
add_shortcode( 'get_email', 'my_get_current_user_email');
Then use a div to wrap the shortcode:
<div id="target-content" style="display: none;">
[get_email]
</div>
Finally, access the content of the Div with JavaScript:
const databox = document.getElementById("target-content");
const dataContent = databox.textContent;
console.log(dataContent)
This work perfectly for what I wanted and I hope it will work for you too.
As per your code
<$php
$val = $myService->getValue(); // Makes an API and database call
echo '<span id="value">'.$val.'</span>';
$>
Now you can get value using DOM, use innerHTML of span id, in this case you don't need to do any call to server, or Ajax or another thing.
Your page will print it using PHP, and you JavaScript will get value using DOM.
<?php
$val = $myService->getValue(); // Makes an API and database call
echo "
<script>
myPlugin.start({$val});
</script> ";
?>
we can do it using php heredoc:
<?php
$inPhpVar = "i am php var";
$ScriptInline = <<<JS
<script>
alert('{$inPhpVar} that used in js code');
</script>
JS;
echo $ScriptInline;
?>
I'd like to replace content within my page based on the URL parameter.
Ideally I'd like to use PHP to get:
if {{parameter is X}} display {{content X}}
if {{parameter is Y}} display {{content Y}}
..for a few pages.
Current set up:
<?php if ($CURRENT_PAGE == "Index") { ?>
<div id="firstDiv">this is the standard page</div>
<?php } ?>
<?php if ($CURRENT_PAGE == "p1") { ?>
<div id-"secondDiv">this is a variation of the page</div>
<?php } ?>
And using include("includes/content.php"); to call the html blocks to the page
The firstDiv displays in index.php as expected, but adding the URL parameter changes nothing - the same div still shows (I'd like it to be replaced with the secondDiv)
It seems $CURRENT_PAGE doesn't like URL parameters - what is the alternative?
Hopefully this makes sense, I'm pretty new to PHP. Happy to provide more details if required.
Thanks in advance for any help.
-- UPDATE --
Thank you for the answers so far!
It seems I missed part of my own code (Thanks to vivek_23 for making me realise this - I'm using a template, excuse me!!)
I have a config file that defines which page is which, as so:
<?php
switch ($_SERVER["SCRIPT_NAME"]) {
case "index.php/?p=1":
$CURRENT_PAGE = "p1";
break;
default:
$CURRENT_PAGE = "Index";
}
?>
Before I learn $_GET, is there a way I can use my current set up?
Thanks again.
-- UPDATE 2 --
I have switched to using the $_GET method, which seems to be working well so far. My issue now is when the parameter is not set it is giving an undefined error. I'll try to remember to update with the fix.
$p = ($_GET['i']);
if($p == "1"){
echo '<div id="firstDiv"><p>this is the first div</p></div>';
}
Thanks to the two answerers below who suggested using $_GET
You can used $_GET like
if($_GET['p']==1){
echo '<div id="firstDiv">this is the standard page</div>';
}else if($_GET['p']==2){
echo '<div id="secondDiv">this is a variation of the page</div>';
}
The other way! you can used basename() with $_SERVER['PHP_SELF']
//echo basename($_SERVER['PHP_SELF']); first execute this and check the result
if(basename($_SERVER['PHP_SELF']) == 'index'){
echo '<div id="firstDiv">this is the standard page</div>';
}else{
echo '<div id="secondDiv">this is a variation of the page</div>';
}
You need to send the parameters on the URL query string, like:
yourdomain.com?p=1
So, with this URL, the query string is "?p=1", where you have a GET parameter named 'p' with a value of '1'.
In PHP to read a GET parameter you can use the associative array $_GET, like this:
$current_page = $_GET['p'];
echo $current_page; // returns '1'
The rest of your logic is OK, you can display one div or the other based on the value of the p parameter.
You can read more about how to read query string parameters here: http://php.net/manual/en/reserved.variables.get.php
I am redirecting to a different page with Querystring, say
header('location:abc.php?var=1');
I am able to display a message on the redirected page with the help of querystring value by using the following code, say
if (isset ($_GET['var']))
{
if ($_GET['var']==1)
{
echo 'Done';
}
}
But my problem is that the message keeps on displaying even on refreshing the page. Thus I want that the message should get removed on page refresh i.e. the value or the querystring should not exist in the url on refresh.
Thanks in advance.
You cannot "remove a query parameter on refresh". "Refresh" means the browser requests the same URL again, there's no specific event that is triggered on a refresh that would let you distinguish it from a regular page request.
Therefore, the only option to get rid of the query parameter is to redirect to a different URL after the message has been displayed. Say, using Javascript you redirect to a different page after 10 seconds or so. This significantly changes the user experience though and doesn't really solve the problem.
Option two is to save the message in a server-side session and display it once. E.g., something like:
if (isset($_SESSION['message'])) {
echo $_SESSION['message'];
unset($_SESSION['message']);
}
This can cause confusion with parallel requests though, but is mostly negligible.
Option three would be a combination of both: you save the message in the session with some unique token, then pass that token in the URL, then display the message once. E.g.:
if (isset($_GET['message'], $_SESSION['messages'][$_GET['message']])) {
echo $_SESSION['messages'][$_GET['message']];
unset($_SESSION['messages'][$_GET['message']]);
}
Better use a session instead
Assign the value to a session var
$_SESSION['whatever'] = 1;
On the next page, use it and later unset it
if(isset($_SESSION['whatever']) && $_SESSION['whatever'] == 1) {
//Do whatever you want to do here
unset($_SESSION['whatever']); //And at the end you can unset the var
}
This will be a safer alternative as it will save you from sanitizing the get value and also the value will be hidden from the users
There's an elegant JavaScript solution. If the browser supports history.replaceState (http://caniuse.com/#feat=history) you can simply call window.history.replaceState(Object, Title, URL) and replace the current entry in the browser history with a clean URL. The querystring will no longer be used on either refresh or back/previous buttons.
When the message prompt ask for a non exsisting session. If false, show the message, if true, do nothing. session_start(); is only needed, if there is no one startet before.
session_start();
if ($_GET['var']==1 && !isset($_SESSION['message_shown']))
{
$_SESSION['message_shown'] = 1;
echo 'Done';
}
Try this way [Using Sessions]
<?php
//abc.php
session_start();
if (isset ($_GET['var']))
{
if ($_GET['var']==1)
{
if(isset($_SESSION['views']))
{
//$_SESSION['views']=1;
}
else
{
echo 'Done';
$_SESSION['views']=1;
}
}
}
?>
Think the question mean something like this?
$uri_req = trim($_SERVER['REQUEST_URI']);
if(!empty($_SERVER['REQUEST_URI'])){
$new_uri_req = str_replace('?avar=1', '?', $uri_req);
$new_uri_req = str_replace('&avar=1', '', $new_uri_req);
$pos = strpos($new_uri_req, '?&');
if ($pos !== false) {
$new_uri_req = str_replace('?&', '?', $new_uri_req);
}
}
if( strrchr($new_uri_req, "?") == '?' ){
$new_uri_req = substr($new_uri_req, 0, -1);
}
echo $new_uri_req; exit;
You can use then the url to redirect without vars. You can also do the same in js.
str_replace() can pass array of values to be replaced. First two calls to str_replace() can be unified, and filled with as many vars you like that needs to be removed. Also note that with preg_replace() you can use regexp that can so manage any passed var which value may change. Cheers!
I'm in the middle of designing a mobile site for our main ecommerce site. Because the site is composed of inflexible legacy code I've opted to look up the users user agent string and identify them as a mobile user each page request. That way no changes to the url structure are needed. This seems to be working nicely so far.
However, I thought it may be kind of cool to use this mobile version so that users can browse our ecommerce site on facebook via iframe (the dimensions are perfect). But, unlike the mobile browsers, I am having trouble finding a persistent way to identify the user as a facebook user. I know facebook sends a $_POST variable the first time a page is viewed via iframe, and I could simply just store that in a session variable and be done with it. The issue that arises though is that what if the user visits with facebook, gets marked as a facebook user in their session, then visits our regular ecommerce site? Well, they'd still be identified as a facebook user and get served the facebook version, which is not ideal.
Maybe you can tackle the problem for another angle and test if the website is loaded from a frame or not?
This is possible with javascript:
if (top === self) {
//not a frame
} else {
//a frame
}
Not sure if it's proper etiquette to answer my own question but I found an answer which is a combo of Hassou's answer and a javascript php detection script.
The script I altered is from here:
http://snippets.bluejon.co.uk/check4-js-and-cookies/check4-js-enabled-v2-phpcode.php
Essentially the idea is to use javascript to submit a form referencing the current url, the result tells you if javascript is enabled... However, the idea can easily be altered to submit a form only if javascript returns true for being in an iframe. You can then pass in the $_POST data into the form so that the $_POST data is carried over (only needed if the $_POST data is referenced within the display layer of your application). Here's the basic idea:
<?php
/* Include head of your application goes here, this should do whatever
session handling code you have and all processing done to the $_POST variables */
// ~~~~~~Full Url Function - Works With Mod_Rewrite~~~~~~~~~ //
// important thing is function will grab all $_GET vars
function fullurlnav()
{
$fullurlsortnav = 'http';
$script_name = '';
if(isset($_SERVER['REQUEST_URI']))
{
$script_name = $_SERVER['REQUEST_URI'];
}
else
{
$script_name = $_SERVER['PHP_SELF'];
if($_SERVER['QUERY_STRING']>' ')
{
$script_name .= '?'.$_SERVER['QUERY_STRING'];
}
}
if(isset($_SERVER['HTTPS']) && $_SERVER['HTTPS']=='on')
{
$fullurlsortnav .= 's';
}
$fullurlsortnav .= '://';
if($_SERVER['SERVER_PORT']!='80')
{
$fullurlsortnav .=
$_SERVER['HTTP_HOST'].':'.$_SERVER['SERVER_PORT'].$script_name;
}
else
{
$fullurlsortnav .= $_SERVER['HTTP_HOST'].$script_name;
}
return $fullurlsortnav;
}
// ~~~~~~~~~~~End Full URL Function~~~~~~~~~ //
?>
<html>
<body>
<?php
// Only run this check if user has been identified as a facebook user in their session
// or if they've been identified via the $_POST['signed_request'], which facebook sends
// upon first request via iframe.
// Doing this removes the check when it's unneeded.
if (!isset($_POST['inIframe']) && ( isset($_SESSION['inIframe']) || isset($_POST['signed_request']) ) )
{
?>
<form name="postJs" action="<?php echo fullurlnav(); ?>" method="post">
<input type="hidden" name="inIframe" value="1">
<?php
// Carry over $_POST
foreach($_POST as $key => $value)
{
echo '<input type="hidden" value="'.$value.'" name="'.$key.'" />';
}
?>
</form>
<script type="text/javascript">
<!--
// If in an iframe
if (top !== self)
{
document.postJs.submit();
}
//-->
</script>
<?php
}
elseif(isset($_POST['inIframe']) && ( isset($_SESSION['inIframe']) || isset($_POST['signed_request']) ) )
{
$_SESSION['inIframe']=1;
}
else
{
$_SESSION['inIframe']=0;
}
if ($_SESSION['inIframe']== 1){
echo 'IS in an Iframe';
}else{
echo 'IS NOT in an Iframe';
}
// echo out rest of your template code
?>
</body>
</html>
It gets a little tricky skating around your page display code output and it's workings, but that's the basic idea i have so far. Technically one could separate the form generation block from the elseif else statements below, and use those above your code before any display output, that may be easier to handle. Note that the above code is untested, just given to provide the basic idea for others with the same issue.