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Pass a PHP string to a Javascript variable (and escape newlines)
I'm working on a project and it's already done, but it needs one more midification and its applying language constants in javascript files.
consider we include a javascript file and in that we have something like this
alert("YOU Have VOTED BEFORE");
easy like that , the script will alert that text
but what if we need to alert a language constant of it :
alert("<?php echo _VOTED_BEFORE?>");
this will be worked only if echo the script like inline of my php codes ...
but, how can we read and include php constants or $vars for a outside JavaScript file ???
For a cleaner structure, I think the best way is to set all the data you get from PHP in one place, i.e. in the HTML you serve via PHP:
<script>
var MyNameSpace = {
config:
something: "<?php echo _VOTED_BEFORE ?>"
}
}
</script>
In the JavaScript file you include afterwards, you can access the value via MyNameSpace.config.something.
This makes it also easier to reuse the message.
There is a way of doing this using a query string in the script path
See my answer here
How to pass variable from php template to javascript
Unfortunately this will break the cache for your js file so weight your options first
<script type="text/javascript" src="script.js?flag=<?php echo _VOTED_BEFORE?>"></script>
for the sake of not writing too much code refer to the link to see how to retrieve the value
Actually, what you had was close to being proper.
<?php
// Valid constant names
define("VOTED_BEFORE", "false");
?>
<script type="text/javascript">
alert("<?php echo VOTED_BEFORE;?>");
</script>
If it's not a PHP file, you cannot include PHP echo functions in it. I suggest that if you want to use a PHP variable in your external js files then declare it as a global in your PHP
file before you reference the external js.
<script type="text/javascript">
var globalvar = '<?php echo _VOTED_BEFORE ?>' ;
</script>
<script type="text/javascript" src="externalfile.js"></script>
Though it's not always a good idea to clutter the global namespace.
You can use cookies to save these constants and read them in via JavaScript or you will have to use AJAX
Related
This question already has answers here:
How do I pass variables and data from PHP to JavaScript?
(19 answers)
Closed 8 years ago.
I have a php file that generates a variable and I would like the variable to be put into a JavaScript function which is called by onclick on the main page. Is this possible to send from PHP to JavaScript?
You can do the following:
<script type='text/javascript'>
document.body.onclick(function(){
var myVariable = <?php echo(json_encode($myVariable)); ?>;
};
</script>
Just write:
<script>
var my_variable_name = <?php echo(json_encode($php_string)); ?>;
</script>
Now it's available as a JavaScript variable by the name of my_variable_name at any point below the above code.
Your JavaScript would have to be defined within a PHP-parsed file.
For example, in index.php you could place
<?php
$time = time();
?>
<script>
document.write(<?php echo $time; ?>);
</script>
If I understand you correctly, you should be able to do something along the lines of the following:
function clicked() {
var someVariable="<?php echo $phpVariable; ?>";
}
A great option is to use jQuery/AJAX. Look at these examples and try them out on your server. In this example, in FILE1.php, note that it is passing a blank value. You can pass a value if you wish, which might look something like this (assuming javascript vars called username and password:
data: 'username='+username+'&password='+password,
In the FILE2.php example, you would retrieve those values like this:
$uname = $_POST['username'];
$pword = $_POST['password'];
Then do your MySQL lookup and return the values thus:
echo 'You are logged in';
This would deliver the message You are logged in to the success function in FILE1.php, and the message string would be stored in the variable called "data". Therefore, the alert(data); line in the success function would alert that message. Of course, you can echo anything that you like, even large amounts of HTML, such as entire table structures.
Here is another good example to review.
The approach is to create your form, and then use jQuery to detect the button press and submit the data to a secondary PHP file via AJAX. The above examples show how to do that.
The secondary PHP file receives the variables (if any are sent) and returns a response (whatever you choose to send). That response then appears in the Success: section of your AJAX call as "data" (in these examples).
The jQuery/AJAX code is javascript, so you have two options: you can place it within <script type="text/javascript"></script> tags within your main PHP document, or you can <?php include "my_javascript_stuff.js"; ?> at the bottom of your PHP document. If you are using jQuery, don't forget to include the jQuery library as in the examples given.
In your case, it sounds like you can pretty much mirror the first example I suggested, sending no data and receiving the response in the AJAX success function. Whatever you need to do with that data, though, you must do inside the success function. Seems a bit weird at first, but it works.
You can pass PHP values to JavaScript. The PHP will execute server side so the value will be calculated and then you can echo it to the HTML containing the javascript. The javascript will then execute in the clients browser with the value PHP calculated server-side.
<script type="text/javascript">
// Do something in JavaScript
var x = <?php echo $calculatedValue; ?>;
// etc..
</script>
I have a JavaScript file which has a hard coded BASEURL variable, this value is then used by other functions in the file.
I would like for this url value to be set dynamically so that I don't need to manually change it for different installs. Is it possible to insert a PHP variable value into a JavaScript file?
Rather than try to mix PHP into javascript files, here's what I do in the HTML template:
<head>
<script>
var BASEURL = "<?php echo base_url(); ?>";
</script>
<script src="/path/to/my_script1.js"></script>
<script src="/path/to/my_script2.js"></script>
</head>
This sets the variable and allows all your embedded scripts to access it. base_url() would be replaced by whatever method you use to fetch the base url with PHP.
Suppose you have a JS file written on the fly by PHP; file1.php
<?php
header('Content-Type: application/javascript');
$var = $_GET['var1'];
echo "jsvar = ".$var.";";
?>
The client-side source code of file1.php?var1=10 will then be
jsvar=10;
There exists several ways:
Load the baseurl via AJAX, but maybe this is to slow, maybe you need it earlier.
let the javascript file running through the php parser. Then you could use inline echos.
The most convenient and easiest way, is to make a <script>var baseurl = '...';</script> in the html/php output of your page.
You will need to make your file a php file, not a js file. From there you can include any PHP tags in the file to work your dynamic magic. The key to make this whole thing work is in the headers, which you will need to set like so:
<?php
Header("content-type: application/x-javascript");
echo 'var js_var = ' . $php_var;
?>
alert (js_var);
This technique can be used to for CSS files as well.
Heredoc worked for me today:
<?php
echo <<<ANYNAME
<script LANGUAGE="JavaScript" type="text/javascript">
<!--
// code ...
var myLatlng = new google.maps.LatLng($lat, $lon);
// code cont. ...
//-->
</script>
ANYNAME;
?>
http://php.net/manual/en/language.types.string.php#language.types.string.syntax.heredoc
php variable in html no other way then: <?php echo $var; ?>
This question already has answers here:
How do I pass variables and data from PHP to JavaScript?
(19 answers)
Closed 8 years ago.
I've read lots of thread on here but I am still unable to get a variable passed from PHP to an external JS file and wondered if someone could assist?
In my PHP file I have the following;
<script type="text/javascript">
var pass_this_variable = <?php $company['website']; ?>;
</script>
<script type="text/javascript" src="/js/track.js"></script>
In the JS file I have the following;
document.write('<IFRAME SRC="$company['website']" WIDTH="300" HEIGHT="400"></IFRAME>');
What I am trying to achieve is an IFRAME be opened and populated with what is contained within $company['website']. I know I can just use IFRAME directly in the PHP file, but this isn't what I have been tasked with for my homework. When I do use IFRAME directly in the PHP file it works fine, and if I specify a static URL in the JS file such as http://www.google.com this also works fine.
Can anyone assist? Thanks
EDIT:
Thanks for the answers so far, however I'm still unable to get it working :(
The frame that I have in track.php (or track.js) won't load the url thats specified in $company['website'], yet if I change it to http://www.google.com its working fine. For some reason the $company['website'] value isn't being passed :(
if you want your external javascript to be dynamic you can make it a php file and give the correct header, example:
<script type="text/javascript" src="/js/track.php"></script>
track.php
<?php
// javascript generator
Header("content-type: application/x-javascript");
?>
document.write('<IFRAME SRC="<?php echo $company['website'] ?>" WIDTH="300" HEIGHT="400"></IFRAME>');
PHP file (don't forget echo and quoting):
<script type="text/javascript">
var pass_this_variable = '<?php echo $company['website']; ?>';
</script>
<script type="text/javascript" src="/js/track.js"></script>
JS file (use pass_this_variable instead):
document.write('<IFRAME SRC="'+pass_this_variable+'" WIDTH="300" HEIGHT="400"></IFRAME>');
You should fix this line:
var pass_this_variable = <?php echo $company['website']; ?>;
Adding echo and it should work
JavaScript provides you the functionality of ajax for the purpose of reading the PHP or text files. Why don't you create the HTML iframe inside a PHP file with your variables parsed and then take back the response and "throw" it inside a div.
The code for your PHP file:
$cmp = $company['website'];
echo '<input type="hidden" id="cmp1" name="cmp1" value="' . $cmp . '" />';
The code for your JavaScript (.js) file to get the PHP file value:
var company = document.getElementById('cmp').value;
Call a PHP file inside the JavaScript source. You can find the tutorial here:
http://www.javascriptkit.com/javatutors/externalphp.shtml.
So your code will be like this:
<script type="text/javascript" src="track.php?company=<?php echo $company['website']; ?>"></script>
In the PHP file you can fetch the value through $_GET variable and use it in the iframe. Make sure to sanitize the input.
How do I enter a <? echo "hello"; ?> in a .js file.
This is a jquery app, therefore the js file.
Thanks
Jean
You would only be able to do this if the PHP interpreter is configured to run on *.js files, which by default it won't be. Quite honestly, I wouldn't recommend this behavior.
What I'd do instead is something like this (This method can be used for CSS files, too.):
<script type="text/javascript" src="js.php"></script>
js.php
<?php
//GZIP the file and set the JavaScript header
ob_start("ob_gzhandler");
header("Content-type: text/javascript");
//Set a JavaScript variable based on PHP work
echo 'var logged_in_user = "'.$_SESSION['username'].'";';
//Require an external script
require_once($_SERVER['DOCUMENT_ROOT']."/path/to/jquery.js");
?>
//More Javascript functions and code here
$(document).ready(function() {
$('#mydiv').tipsy();
});
<?php
//Flush the output buffer
ob_end_flush();
?>
I personally do this for many reason.
I have many jQuery files I want to include, but I don't want my browser doing 5+ HTTP requests. Including them all in one file means less HTTP requests.
GZIP! I'm significantly reducing the size of the file be transferred and that speeds things up for the visitor.
It's a central location to add, remove, or modify my JavaScript for the whole site. I can even use $_GET checks to make certain scripts conditional based on how I wrote the <script> tag.
For example, <script type="text/javascript" src="js.php?var=1"></script>. I can then check $_GET['var'] within the js.php file.
You regularly don't use PHP within your JavaScript files. Javascript is a client-side language which is interpreterred in your web browser. PHP is run on the web server.
However, if you need to pass data from your PHP-code to your javascript document, you can do something like:
$js = "<script> myObject = " . json_encode($your_data) . " </script>";
print $js;
If you do this in your <head>-part of your HTML-document, you will have access to myObject in other JS files you load after that.
$your_data can be an array or any kind of object, string or integer. Look for PHP JSON around the interwebs.
I think is not possible to enter a php in the js file, but:
try to create an element div for example or an input ...
and then use this functions to get the value of the div tag.
function AddHiddenValue(oForm) {
var strValue = document.getElementById("city").value;
alert("value: " + strValue);
var oHidden = document.createElement("input");
oHidden.name = "printthisinput";
oHidden.value = strValue;
oForm.appendChild(oHidden);
}
It come from another object form (select .. )
document.getElementById("city").value;
Ok guys here is the answer
The Q: I want to input a value for a variable into a .js file, php tags are not permitted and the js would throw an error.
The A: write a
<script> <? var value_pass = echo "hello"; ?> </script> before the said .js file
In the said .js file
var value=value_pass;
So there is no need to have any of the ob_end_flush.
If this is not viable please let me know.
Thanks
Jean
I can access a PHP var with Javascript like this:
<?php
$fruit = "apple";
$color = "red";
?>
<script type="text/javascript">
alert("fruit: " + "<?php echo $fruit; ?>"); // or shortcut "<?= $fruit ?>"
</script>
But what if I want to use an external JS file:
<script type="text/javascript" src="externaljs.js"></script>
externaljs.js:
alert("color: " + "<?php echo $color; ?>");
You don't really access it, you insert it into the javascript code when you serve the page.
However if your other javascript isn't from an external source you can do something like:
<?php
$color = "Red";
?>
<script type="text/javascript">var color = "<?= $color ?>";</script>
<script type="text/javascript" src="file.js"></script>
and then in the file.js use color like so:
alert("color: " + color);
You can also access data from php script in Javascript (I'll use jQuery here) like this
Create input hidden field within you php file like this
<input type="hidden" id="myPhpValue" value="<?php echo $myPhpValue ?>" />
in your javascript file:
var myPhpValue = $("#myPhpValue").val();
//From here you can the whaterver you like with you js Value
if(myPhpValue != ''){
//Do something here
}
This will do the job as well :)
What I've seen done is let .js files run through the php interpreter. Which I can not recommend.
What I do recommend is fetching the values through AJAX and have the PHP file return the value to the JS file. Which is a much cleaner method.
First of all you have to understand that no program can actually have access to the other program's variable.
When you realize that, the rest is simple.
You can either set up a js variable in the main file and then include your external js, or make this external js dynamic, generated by PHP as well
What you likely want, is called Asynchronous JavaScript and XML (AJAX): http://www.w3schools.com/ajax/default.aspa
Basically, imagine being able to send messages from the clients JavaScript to your PHP scripts on the server. In the example you gave (externaljs.js), you would have the script ask the server what $color is, via HTTP. You can also point the script tag at a PHP script that generates the JavaScript you want. It depends on what you need to do.
It helps to have some understanding of taint checking, data verification, and security ;)
As the others are saying, javascript doesn't have access to php variables. However, it does have access to the DOM. So, you can use php to add attributes to some page element. And then you can access those attributes with javascript.
e.g. <div id='apple' class='red'> is completely available to javascript
Don solution is good, furthermore if you want to use a php array in an external javascipt this can help you:
PHP:
<?php
$my_php_array = [];
?>
HTML:
<script type="text/javascript"> var my_js_array = <?php echo json_encode($my_php_array);?> ; </script>
<script src = "../public/js/my-external-js.js"></script>
Javasript: (You can now use the array like a normal Javascript array)
my_js_array[0]
my_js_array.length
externaljs.js is a static file. Of course it can't access PHP data. The only way to pass PHP data to a js file would be to physically alter the file by writing to it in your PHP script, although this is a messy solution at best.
Edit in response to Ólafur Waage's answer: I guess writing to the js file isn't the only way. Passing the js through the PHP interpreter never crossed my mind (for good reason).
<script type="text/javascript" src="externaljs.js"></script>
You could change it to
<script type="text/javascript" src="externaljs.php"></script>
And the PHP script could just write JavaScript like that :
<?php
$fruit = "apple";
echo 'var fruit = '.json_encode($fruit);
...
Though using AJAX like said Sepehr Lajevardi would be much cleaner
2017-2018 and above solution:
Since nobody bringed it up yet and I guess no one thought of combining the functions base64_encode and json_encode yet, you could even send PHP Array variables like that:
index.php
<?php
$string = "hello";
$array = ['hi', 'how', 'are', 'you'];
$array = base64_encode(json_encode($array));
Then you could just load your desired js file with the parameter for a query string like this:
echo '<script type="text/javascript" src="js/main.php?string='.$string.'&array='.$array.'">';
Then js/main.php will look like this for example. You can test your variables this way:
js/main.php
<?php
if ($_GET['string']) {
$a = $_GET['string'];
}
if ($_GET['array']) {
$b = $_GET['array'];
}
$b = json_decode(base64_decode($b));
echo 'alert("String $a: + '.$a.'");';
echo 'alert("First key of Array $array: + '.$b[0].'");';
exit();
?>
The following will then output when you open your index.php. So you see, you don't open js/main.php and you still got the javascript functionality from it.
You can include() them just as you would anything else:
<?php
$fruit = "apple";
$color = "red";
?>
<script type="text/javascript">
<?php include('/path/to/your/externaljs.js'); ?>
</script>
This will basically render the external file as inline js. The main disadvantage here is that you lose the potential performance benefit of browser caching. On the other hand, it's much easier than re-declaring your php variables in javascript.
You cant do that and dont try to as this is not a recommended approach, However you can pass php variables as a function parameters to function written in external js