onreadystatechange

[niladhar8@gmail.com]

Below in my code i wish to understand the role of onreadystatechange called with the xmlhttp object. i read on the web that it gets a value from 1 to 4 ranging on the status of the process but my question is we still havent opened the connection and sent the object to the server (open, send) which follows this statement so how do we know the value.....

and also statechange 's address is being assigned to the object so its working as a function pointer and thus there is no ().... am i correct?

var url="get_user.php";
url=url+"?q="+str;
url=url+"&sid="+Math.random();
xmlhttp.onreadystatechange=stateChanged;
xmlhttp.open("GET",url,true);
xmlhttp.send(null);

[PeejAvery]

http://w3schools.com/ajax/ajax_xmlhttprequest.asp