Cross site Ajax Request

            How to request data from a server in a different domain?

                  In my previous post I had shown you “How to create watermark for pdf using php  script ?”. Today I am going to write about jquery cross site ajax call to retrieve data from different domain. We can solve this using ‘JSONP’.
Let us know first “ What is JSONP ? “


JSONP is JSON with padding. JSONP is a technique that allows you to transfer JSON data across multiple domains. For security reasons browser does not allow script from remote domain to run. We are going to use JSONP to solve this. Cross domain ajax refers to the idea of making requests across domains in opposition to the same origin restriction. Padding or prefix  is typically name of callback function. The response to the JSONP is not json and not parsed as json also, It is javascript expression which invokes a function call on some json formatted data.
How is it works ?

It’s makes sense when used with script tag. For each new JSONP request browser add a new <script> tag or use existing one. The url request pointed to by the <script>’s src attribute returns JSON data, with a function call wrapped around it.

You can follow below script to do ajax request to cross site. For client side jquery –


          dataType: ‘jsonp’,
          url : ‘’,
          data: ‘userid=204’,
          jsonp: ‘js_callback’,
          success: function() {
            // Do your stuffs on
           alert(“Successfully requested cross domain with jquery ajax ”);

Php script given below :

function getuserdetails() {

       $data = array();
       $data  = getuserDataBYID($_GET[‘userid’]);
       echo $_GET[‘js_callback’].”(”.json_encode($data).”);”;


         Jsonp is fastest and easiest way to get json data from remote servers with javascript. It allowing including script tags from remote servers allows the remote servers to inject any content into a website. So if the remote servers hae vulnerabilities that allow javascript injection. So in that way it’s increased the risk also.

Hope this post will help you all to know about cross domain ajax request using JSONP callback. Keep visiting for new interesting posts here and please join my groups in linkedin, facebook to keep up to date. Please share your ideas here and do post if you have any new things to share with everyone. If you like my post please leave a comment here. All the best. Have a good day ahead.

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  1. Thanks for sharing this useful info. Keep updating

    same way.
    Regards,Siddu Corporate Training

  2. Hi Can you tell me how to POST values by Jsonp


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