var javascript_variable = $("#ctl00").text();
<?php $php_variable = ?> document.write(javascript_variable); <? ; ?>
I want to pass the above javascript_variable into php_variable. This code is giving me an error. Any ideas on how?
You cannot do that.
PHP is executed on your server. Javascript on the otherhand is executed on your client's machine in the browser.
There are two different execution context. While you can pass a PHP variable into Javascript, you cannot do the opposite since PHP is executed first and the JavaScript code is the output of your PHP code.
If you want to send a Javascript variable to PHP, you have to do with in a separate request either via a cookie or an AJAX request. Here's an example:
$.ajax({
url: 'receivingScript.php',
data: {'value': $("#ct100").text()}
});
Related
I have some PHP code inside the script so I need
the JavaScript value as a PHP variable, as follows:
<script>
;
var js_var = 123;
var php_var = <?php js_var ?>;
alert(php_var);
;
</script>
Using jQuery to send the value to a PHP page will return the value but not as a PHP variable:
$.get("page.php", {js_var_name: js_var}, function(data) {alert(data)});
I tried also all jQuery AJAX functions: load(), post() and the ajax() method, none of them pass back the value of PHP as above requested.
Is it possible to implement the above with jQuery?
Likely you have a syntax issue with :
var php_var = <?php js_var ?>;
Unless you used define() your php variable should start with $ and you need to echo it so that it gets printed to the page
var php_var = <?php echo $js_var ?>;
If you are assuming that php will read the prior javascript js_var=123 it won't. Javscript is a client side language and php is server side.
You cannot simply mix PHP and JavaScript. The former is executed on the server, the latter on the client, namely in the user's browser. In order to hand a value from PHP to JavaScript you need to output JavaScript code via PHP or do a AJAX-Request to a PHP-Script, as you tried. When using AJAX, it is the easiest solutions to have PHP script that returns a JSON string. When calling this script using $.get() the result will be stored in a JavaScript variable and you can access all the values from there.
Take a moment and a deep breath...and then start thinking about your scopes again.
i am passing variable from javascript php with the following code by using cookie.
<script type="text/javascript">
function gTest() {
var country = 'hello testing';
document.cookie = 'name=document.write(country);' ;
document.write(country);
}
gTest();
</script>
<?php
echo "<br>";
var_dump($_COOKIE['name']);
?>
it works fine if we change to
document.cookie = 'name=hello' ;
i want to pass variable value to php in same page...i don't want to send to another page.
thanks
$_COOKIE is populated with the data sent from the browser to the server.
The JS to change the cookie won't run until the response is sent back and the JavaScript is executed.
The values in $_COOKIE won't update until you make a new HTTP request.
You can use XHR.
JavaScript (using jQuery):
$.ajax('script.php', {
data: { 'name': 'hello' }
});
PHP:
var_dump($_GET['name']);
You cant.
Ok, I think I got to explain. On your page, there is the Javascript first, then the PHP code, but it doesnt execute in that order.
First the server execute the PHP code, send the page as HTML and the javascript is executed on the client side.
If you really dont want to reload the whole page, the only way to do it is to use an ajax request to a page where your PHP code is. Simply use JQuery and replace your PHP code with this :
$('#result').load('showCookie.php');
Content of showCookie.php will be your var_dump and the page will do exactly what you want, except that you have called an additional page with JQuery.
I want the value of JavaScript variable which i could access using PHP.
I am using the code below but it doesn't return value of that variable in PHP.
// set global variable in javascript
profile_viewer_uid = 1;
// php code
$profile_viewer_uid=$_POST['profile_viewer_uid'];
this gives me the following error :-
A PHP Error was encountered
Severity: Notice
Message: Undefined index: profile_viewer_uid
Another php code i used which give empty value
$profile_viewer_uid = "<script language=javascript>document.write(profile_viewer_uid);</script>
When I echo it shows nothing.
Add a cookie with the javascript variable you want to access.
document.cookie="profile_viewer_uid=1";
Then acces it in php via
$profile_viewer_uid = $_COOKIE['profile_viewer_uid'];
You will need to use JS to send the URL back with a variable in it such as:
http://www.site.com/index.php?uid=1
by using something like this in JS:
window.location.href=”index.php?uid=1";
Then in the PHP code use $_GET:
$somevar = $_GET["uid"]; //puts the uid varialbe into $somevar
Here is the Working example: Get javascript variable value on the same page.
<script>
var p1 = "success";
</script>
<?php
echo "<script>document.writeln(p1);</script>";
?>
You might want to start by learning what Javascript and php are. Javascript is a client side script language running in the browser of the machine of the client connected to the webserver on which php runs. These languages can not communicate directly.
Depending on your goal you'll need to issue an AJAX get or post request to the server and return a json/xml/html/whatever response you need and inject the result back in the DOM structure of the site. I suggest Jquery, BackboneJS or any other JS framework for this. See the Jquery documentation for examples.
If you have to pass php data to JS on the same site you can echo the data as JS and turn your php data using json_encode() into JS.
<script type="text/javascript>
var foo = <?php echo json_encode($somePhpVar); ?>
</script>
If you want to use a js variable in a php script you MUST pass it within a HTTP request.
There are basically two ways:
Submitting or reloading the page (as per Chris answer).
Using AJAX, which is made exactly for communicating between a web page (js) and the server(php) without reloading/changing the page.
A basic example can be:
var profile_viewer_uid = 1;
$.ajax({
url: "serverScript.php",
method: "POST",
data: { "profile_viewer_uid": profile_viewer_uid }
})
And in the serverScript.php file, you can do:
$profile_viewer_uid = $_POST['profile_viewer_uid'];
echo($profile_viewer_uid);
// prints 1
Note: in this example I used jQuery AJAX, which is quicker to implement. You can do it in pure js as well.
PHP runs on the server. It outputs some text. Then it stops running.
The text is sent to the client (a browser). The browser then interprets the text as HTML and JavaScript.
If you want to get data from JavaScript to PHP then you need to make a new HTTP request and run a new (or the same) PHP script.
You can make an HTTP request from JavaScript by using a form or Ajax.
These are two different languages, that run at different time - you cannot interact with them like that.
PHP is executed on the server while the page loads. Once loaded, the JavaScript will execute on the clients machine in the browser.
In your html form make a hidden field
<input type="hidden" id="scanCode" name="SCANCODE"></input>
Then in your javascript update the field value by adding;
document.getElementById("scanCode").setAttribute('value', scanCode);
This could be a little tricky thing but the secure way is to set a javascript cookie, then picking it up by php cookie variable.Then Assign this php variable to an php session that will hold the data more securely than cookie.Then delete the cookie using javascript and redirect the page to itself.
Given that you have added an php command to catch the variable, you will get it.
You need to add this value to the form data that is submitted to the server. You can use
<input type="hidden" value="1" name="profile_viewer_uid" id="profile_viewer_uid">
inside your form tag.
i want to pass a javascript string to php ... WHICH is RIGHT after the code .. in the script.
<script type="text/javascript">
var myvar = "mytext" ;
<?php echo myvar ; ?>
</script>
this does not work.
What should i do ?
When someone visits a website, this is generally what happens:
Their browser sends a request to the server.
The server evaluates that request.
The server realizes, "Egad, the page they're requesting has PHP!"
The server evaluates the PHP, and only sends the results to the browser.
The browser parses the content that it receives.
The browser realizes, "Egad, the page I received has JavaScript!"
The browser evaluates the JavaScript, entirely on the client's machine.
So PHP and JavaScript are basically at different ends of the process. Only the server handles PHP, and only the client handles JavaScript.
To "give" a string to PHP, you'd have to make a request of the PHP page, sending that string as a GET variable:
http://www.yourdomain.com/some_php_page.php?myvar=mytext
There are a few ways to do this with JavaScript.
If you only care about making that request on the PHP page, and you don't need to worry about receiving any information back, you can just create an image and use the URL as the source:
var fakeImg = new Image();
fakeImg.src = 'http://www.yourdomain.com/some_php_page.php?myvar=mytext';
Even though you're requesting an image, the server doesn't know that, and will process your request by calling the PHP evaluating it, etc.
You can make an actual AJAX request. Start by creating an XMLHttpRequest object:
var xhr = window.XMLHttpRequest ? new XMLHttpRequest() : new ActiveXObject('Microsoft.XMLHTTP');
There are some issues in IE with cached responses on AJAX requests, so make the url unique:
var url = 'http://www.yourdomain.com/some_php_page.php?myvar=mytext&unique=whatever';
Tell your XHR where you want it to go, and how you want it to get there:
xhr.open('GET', url, true);
// The "true" parameter tells it that we want this to be asynchronous
Set up a method that will check for when a response is received:
xhr.onreadystatechange = function () {
if (xhr.readyState === 4 && xhr.status < 400) {
success(xhr.responseText);
}
};
And finally, send the request:
xhr.send(null);
// We set "null" because some browsers are pissy
Some notes to keep in mind:
You have to build the success function yourself, to handle the string that your PHP page will return.
You can pass that function xhr.responseXML if you want, but that's usually just a hassle for me.
Using onreadystatechange the way I have will (I believe) introduce memory leaks in some versions of IE
PHP is executed server side while javascript is client side, so that means that the PHP is already executed when you're sending your javascript code.
You might want to look into AJAX instead.
You should get the difference between client side and server side code clear. The variable you are introducing in the php code isn't assigned before because that variable is set at the client. So your code example is in essence wrong. If you want a value that is present at the client (javascript) to be available at the server (php), you need to do something with the xmlhttprequest object of javascript (also know as ajax).
You can do the other way around though...print a php value in javascript. This is because the script is than created server side and send to the client before it is being processed by the browser.
Not sure what you are trying to reach but maybe this helps a bit.
Your example is somewhat confusing:
<script type="text/javascript">
var myvar = "mytext" ;
<?php echo myvar ; ?>
</script>
Because if I do this:
<script type="text/javascript">
<?php $myvar = "mytext"; ?>
var myvar = "<?php echo $myvar; ?>" ;
</script>
Then it sets the JavaScript value of myvar to the PHP value of $myvar so they both stay the same. If you're trying to do something else you need to expand your example.
I'm using jquery ajax can i use php code in success: function(html){} ??
No, jquery/JavaScript code is executed at the client side. You can either write JavaScript/jQuery code or preprocess the answer to the XHR request in php.
No, not directly, as JavaScript ist executed on the client side, and PHP is executed on the server.
A workaround would be to send another AJAX-Request from your success-function. But it can only do things on the server side, not on the client side.
If you just want to download a file from your callback function, use location.href = url. The URL can be a server side PHP script serving the data stream, or a real file.
Yes.
For instance, you could do:
success: function(html) {
<?php echo 'alert("Hello, World!");' ?>
}
Since JS is all client side and PHP is server side, the two cannot be executed within each other synchronously. However, you can use AJAX to ask PHP to execute code on values, but if you already have an AJAX query to PHP going, why not just do it then.
You use PHP indirectly anyhow. There is no need to note in the success function:
$.ajax({
url: "execute.php",
success: function(html){}
And the html comes directly from the execute.php script. And this is where you do any PHP stuff like:
<?php echo "<div>" . php_stuff() . "</div>"; ?>
Think of the PHP script as the first half of the execution, and the jQuery success: callback as the second part of the AJAX call.