Please bear up with me, I'm new to PHP. I'm using a mixture of PHP and jQuery on the same page. I need to pass variables from jQuery to PHP. All examples I came across describe how to pass variables to a PHP file on the server which I don't want. So far I manged to convert object to JSON using jQuery $.toJSON();
My question is: is it possible to pass jQuery data to php code if both jQuery and PHP reside on the same page?
Here is my code so far:
var myObject = {name: 'Tomas', age: 38};
var encoded = $.toJSON( myObject);
var name = $.evalJSON( encoded ).name;
var version = $.evalJSON(encoded).age;
No it is not possible since PHP is not a client side script but rather a server side script. What that means is that by the time the data is given to the client the PHP script would have most likely already finished running. The following demonstrates the relationship between PHP and JavaScript:
Server -> PHP -> Client (Browser) -> Javascript
Therefore, it is impossible to have javascript communicate to PHP on the same page. What you can do is use Ajax to call a server side file like you said - but I'm afraid that is as much as you can do in terms of PHP and JavaScript Communication
Related
This question already has answers here:
How can I pass variables from JavaScript to PHP?
(2 answers)
Closed 9 years ago.
I want to pass a variable from a function in JavaScript to PHP that is also inside the JavaScript function.
For Example:
myfunction('qwerty');
<script>
myfunctionjs(x)
{
<?php echo $x?>
}
</script>
note: code above is just a sample
Your code sample, while it expresses what you want quite clearly, should also show how impossible it is.
PHP is a server-side language whereas javascript is a client-side language. The only way for javascript to "talk" to PHP is to submit a request to the server. You can do this either through a standard HTTP-GET request or a POST request (through a form submission, or more commonly via Ajax).
The PHP isn't inside the JavaScript function. The PHP code is executed on the server.
When the Javascript is executed, the code looks like this:
myfunction('qwerty');
<script>
myfunctionjs(x)
{
alert(x); //or whatever $x is
}
</script>
If you want to pass 'x' to a PHP script, you'll have to make an AJAX request.
You can't have javascript telling PHP to do something inline. JavaScript runs client side, while PHP runs server side.
Instead, you need to have your javascript send the data to your server, and you'll have PHP do something when receiving that second request.
If you are using jQuery, have a look at the ajax method for example on how to send data: http://api.jquery.com/jQuery.ajax/
Passing variable from javascript to php right away is not possible. You will have to use AJAX for this. You have to understand the difference between server-side scripting and client-side scripting.
https://softwareengineering.stackexchange.com/questions/171203/what-are-the-difference-between-server-side-and-client-side-programming
Read the above link and it will give you a full understanding of the process. if you have any issues let me know.
Read more
I am working on a project where I used ajax for asynchronous DB access.
I store the value in JavaScript variable as follows..
var content=xmlhttp.responseText;
now what I wanted is to pass this value to the php module on same page..
Please suggest me..its urgent
You'll have to make a separate AJAX request to another script to achieve this. PHP is server-sided and therefore cannot directly interact with the client.
You should handle the data (which you are assigning to content) in PHP because, as the other answers here tell you, PHP is server-side and JavaScript is on the client. If you are getting this data from a page you control, instead of var content = xhr.responseText; just modify the data BEFORE you send it. For example, if you are making an AJAX call to a process.php file on your server to get the data you are otherwise assigning to content in JavaScript, be sure to handle the data in process.php PRIOR to echo()'ing the data (which you are then storing inside content on the client):
In process.php:
// below is the normal server script which you are storing in content on the client
// echo $result;
// instead, we are going to operate on the data first:
return doSomething($result);
Then on the client:
var newContent = xhr.responseText;
And the newContent variable will contain the data you previously wished to modify with PHP. If you DO NOT have control of the server script which you are calling with AJAX, then as mentioned here already, you will need to send a SECOND AJAX call to the server with your PHP, and use $_GET or $_POST to retrieve that content data and then play with it there.
Am unclear about your need to pass value from javascript to php.
But I can give you,
A non-recommended but working approach towards your problem:
You said, you are making an Ajax call at first. While processing the corresponding server side php function, Store the response value (value of xmlhttp.responseText) into a $_SESSION variable. Finally Reload the page (using location.reload()) inside the ajax response handler function.
And a recommended approach towards your problem:
You might have added some if-else control-flow structures in the php code and expecting to execute them after getting the ajax response value (sadly you cannot do that). So if you do have some logic like that, then convert those if-else conditions to corresponding Javascript code. May be a javascript function and call that function by passing the ajax response value to it. This new function will use your ajax response value and make changes in some parts of your webpage by applying necessary logic.
I have a Javascript variable which I am setting a PHP variable to.
function cancel(number) {
var message = "<?= $message[" + number + "]; ?>";
}
$message is an array. "number" is the element of the array I want to set message to. Basically, I want to set a Javascript variable to a PHP variable using a Javascript variable as the element picker. So if "number" was 2, it would select:
$message[2];
However, the above approach doesn't work, and I'm not even sure if this is possible.
It isn't. Use XHR to retrieve the value from the server.
It doesn't seem at all possible; PHP is evaluated server-side, and javascript is evaluated client-side. So PHP would see it as $message["+number+"], and try to find the value at the index of "+number+". You'd probably have to do something like an AJAX request to get the data you're looking for.
What you are doing isn't possible; since php is a server-side language, it's executed first, and the js is executed after; there isn't any way to control which is executed first. You must retrieve the variable using AJAX.
Something like this will work:
<script type="text/javascript">
var messages = <?= json_encode($message) ?>;
function cancel(number) {
var message = messages[number];
}
</script>
Of course this will output the entire array in the JavaScript source. If it is large, then you are better off using AJAX.
Tip: if you "view source" it should be painfully obvious why your method doesn't work.
You simply cannot do this using this methodology. PHP is server-side code, meaning that it runs on the server, while JavaScript is client-side code, meaning it runs on the client, or your browser.
Once the PHP runs, it generates an HTML document and sends that document in the response to the browser. Once that's complete, the only way you can get data back to the server is to send it via a form POST, send it via AJAX, or send it via script tag remoting.
Consider looking at some examples on the Internet of how to POST data back to the server via a form and via AJAX. It's clear you're struggling with some concepts regarding how to properly architect your program, and looking at some examples would be a great way for you to learn and master these techniques.
PHP Submit Form Example
PHP Tutorial
You need to use AJAX call to resolve your issue.
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.
$('myBtn').on("click",function(){
var parent= $(this).parent();// will give you the Parent Object of the button, that has been clicked
});
I need to send var parent to php so it knows where to display the html data (in the correct are div/class, how would i do this.
The short answer is that "You can't".
Communication between the browser (where your JS is running) and the server (where the PHP is running) is handled via HTTP. If you want to send a JavaScript object then you have to serialise it to a string and deserialise it at the other end. There is no sane way to represent an HTMLElementNode (or a jQuery object that wraps on) in that process (not least because PHP doesn't usually represent HTML in a DOM and when it does it won't be the same DOM instance as the browser is using).
Usually in this type of situation, you would request some data from PHP (possibly using one of jQuery's ajax methods) and then use JavaScript to turn it into DOM elements and insert it into the document.
Try JSON and Ajax (XMLHttpRequest) as the "client to server" mechanism
JavaScript is evaluated on client-side, when PHP is server side. You don't have trivial way to do it.
If the html data is not already generated, you would have to make a new request to the server, preferrably by the jQuery $.get function, then pass the output (again via jQuery) to the parent element.
Please use Jquery and use $.ajax for this purpose
$.ajax({
type: "POST",
url: "yourPHPPage.php",
data: "parentvar="+parent,
//parent is a javascript variable
success: function(msg){
//Message received from server,
// if you would write some code in echo there, like echo "hello";
// you would get that in msg.
}
});
to access this variable on php, use $_POST["parentvar"];
You can also send multiple values by concatinating them with & operator.
Like data:"parentVar="+parent+"&name=atif&age=23"; etc
Please let me know if further help needed.
Further help on
http://api.jquery.com/jQuery.ajax/
As far as I know, you can't pass a DOM object directly to the server -- there's too much information stored for it to be practical. You could send the HTML of the object though.
Here's an example that sends the HTML to the server. You would process it, but we just echo it back.
http://jsfiddle.net/hLD4F/
Try clicking on any of the buttons, and it will send a request. In PHP you could access this information via $_POST['html'].