AJAX work with PHP

ajax increase the web page's interactivity, speed, and usability.

PHP Ajax Example

how a web page can communicate with a web server while a user fill a form (e.g gmail):

start type character in first name field then run js code:




first step : first a user type a character in the first name input field the background javascript code deal with it and run code, look this javascript function code :

 function    ajaxrun(value){
                                     var  xmlhttp = null;
                 if  ( value <= 0 ){
                    document.getelementbyid ("fn").innerhtml="";
                 if ( window.xmlhttprequest ){
                       xmlhttp  = new  xmlhttprequest();
                     }else {
                             // code for ie6,  ie5
                             xmlhttp = new  activexobject( "microsoft.xmlhttp");
     xmlhttp.onreadystatechange = function(){
             if ( xmlhttp.readystate==4 && xmlhttp.status==200){
             document.getelementbyid("show").innerhtml= xmlhttp.responsetext;
     xmlhttp.open("get", "ajaxhandler.php?v="+value, true )
        <p>start type character in first name field then run js code:</p>
<p>first-name:<input type="text"  name="fn" id="fn"  onkeyup="ajaxrun(this.value)"/></p>
<p>last-name:<input type="text"  name="ln"  id="ln"  onkeyup="ajaxrun(this.value)"/></p>
<p>age<input type="text"  name="ag" id="ag"  onkeyup="ajaxrun(this.value)"/><p>
<p>output value: <span id="show"></span></p>

Server Side PHP File

website visitor visit the site and type character in first name field then the keyup mouse event trigger and ajax object send a background request to server and a server side php code handle this request and send back response object, look this server side php code:

           $urlvalue =  $_get['v']; // get the v parameter from url
           if ( strlen($urlvalue)  > 0 ){
                $response = $urlvalue;

                echo  "the value send by visitor : ". $response;
          } else{
                   echo  " please enter a value in form name field ";