Question

150

Calling PHP functions in Javascript using AJAX

rated 0 times [ 153] [ 3] / answers: 1 / hits: 26630 / 12 Years ago, mon, november 12, 2012, 12:00:00

I have a javascript file and I want to call a function on the php server side and return the result back to the client side using ajax, but I am not sure how to make the request to the specific php function.

Here are my files:

The javascript file basically retrieves the username from the html form, and I want to send that username to php and check against the database for availability.

In something.js:

function check_availability()

{

    var username = $.trim(document.getElementById('usernameField').value);

    var xmlhttp= new XMLHttpRequest();



    // not sure how to make the request here to check_availability() under php

}

The PHP file will just check the username thats being passed from the js file against the database, if its available return true, else false.

In something.php:

    class Something_Model {

    private $data;

    private $table;



    public function __construct() {

        $this->data = new udata(DBSERVER, DBUSERNAME, DBPASSWORD, DBNAME);

    }



    # check for username availability

    public function check_availability()

    {

        // make the check here, but needs to retrieve username from js file

        echo here;

    }

}

So, inside the Something_Model class, I want to make the check_availability() call from javascript, can someone give me an example to make this ajax call? Also, how do I return the result back to the javascript? Do I need to encode it as a JSON obj?

Thanks a lot.

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jesse

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2 Years ago

answered 12 Years ago jazminuniquer · Accepted Answer

You can't call a function in PHP directly - but you can call a PHP page that in turn can call the PHP function. For example...

service.php

include_once('something.php');

$model = new Something_Model();

$model->check_availability();

something.js

function check_availability() {



    var request = new XMLHttpRequest();

    request.open('GET', 'http://yoursite/service.php', false);

    request.send();



    if (request.status === 200) {

      alert(request.responseText);

    }

}

I have used a really simple example of an XMLHttpRequest - this example actually blocks while the request is made. In reality you may want to use a callback and allow it to run asynchronously but I wanted to keep the answer as short as possible.