pls i need an ajax loader script for my php site. i want the loading.gif to display when clicking the login button.thanks

If you're looking for a full scale solution, you might want to look here: http://woork..com/2007/10/login-using-ajax-and-php.html

But if you looking for the concept to integrate into something you've already built... Stack Overflow style//

drop jQ in your page (http://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js)
assuming the page that's processing your login is: login.php

//calling the jQ on ready function
(function($) { 
//now the ajax method of jQ is called...

$.ajax({
url: "login.php",
beforeSend:  function() { $("#loading.append("<img src="http://logd.tw.rpi.edu/files/loading.gif"></img>") /** this is where you do the loading thing assuming you're loading it into a div with ID of "loading"*/
success: function(data, xhr){
 // do your xhr checks...if(xhr.success){
 $("loading".html(data);
}

});

}(jQuery));

Generally, the idea is that simple with jQuery.