title: delete session variable in php
body: <p>i create a webpage in that i use session variables , when i click logout i clear the session variables using ajax , it working fine in IE , But when i use firefox sometimes the session is not destroyed , the code i used to clear session is [when i click logout button]</p>
  
  <p><code>function floadhomepage(){</code></p>
  
  <pre><code>    ajaxFunction();
  //alert('Logout clicked');
  window.location.replace("index.php");
  </code></pre>
  
  <p>}</p>
  
  <pre><code>function ajaxFunction()
  var xmlhttp;
  if (window.XMLHttpRequest){
    // code for IE7+, Firefox, Chrome, Opera, Safari
    xmlhttp=new XMLHttpRequest();
     }
  
  
  else if (window.ActiveXObject){
  // code for IE6, IE5
    xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
  }
  </code></pre>
  
  <p>else {</p>
  
  <pre><code>  alert("Your browser does not support XMLHTTP!");
  }
  xmlhttp.onreadystatechange=function(){
  }
  xmlhttp.open("GET","logout.php",true);
  xmlhttp.send(null);
  }
  </code></pre>
  
  <p>in logout.php file contain the folowing code </p>
  
  <pre><code>&lt;?php
  session_start();
  session_destroy();
  unset($_Session['session variable name']);
  ?&gt;
  </code></pre>
  
  <p>Please guide me to find the solution 
  Thanks in advance..</p>