Few tips while using Ajax

While using Ajax in your application , dont assign

xmlHttpObject.onreadystatechange=null.

Because some browsers does not allow it.They neither show a warning nor an error. Especially IE does not support this case.

Instead replace that with
xmlHttpObject.onreadystatechange = function(){};

Similarly while using "POST" method in ajax, you need to specify some header
informations like Content-type,Content-length and Connection.

for example,

var postdata="your data that is to be submitted"
var url="http://www.test.com/servlet/testservlet";
xmlHttpObject.open("POST",url,true);
xmlHttpObject.onreadystatechange = function(){};
xmlHttpObject.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
xmlHttpObject.setRequestHeader("Content-length", postdata.length);
xmlHttpObject.setRequestHeader("Connection", "close");
xmlHttpObject.send(postdata);