Convert Joomla 1.5 AJAX into Joomla 1.7

Joomla 1.5 AJAX Syntax

var a = new Ajax( url, {

 method: 'get',onComplete: function(){

 alert("AJAX is Working in Joomla 1.5")},

 update: element

}).request();

Joomla 1.6/1.7 AJAX Syntax

var a = new Request.HTML({

 url: url,

 method: 'get',onComplete: function(){

 alert("AJAX is Working in Joomla 1.7")},

 update: element

}).send();

Joomla 1.5 above AJAX syntax is not working in Joomla 1.7 because in Joomla 1.7 AJAX is not defined in mootools. so this perticular Joomla 1.6/1.7 AJAX syntax is properly working in Joomla 1.7 and in Joomla 1.6 also.