add: httpPost.onreadystatechange = function () { if (httpPost.readyState == 4) callback (httpPost); }; 
context: function WebForm_httpPost (url, data, callback){	var httpPost = null;		if (typeof XMLHttpRequest != "undefined") {		httpPost = new XMLHttpRequest ();		httpPost.addEventListener ("load", function () { callback (httpPost);}, false );	} else {		if (axName != null)			httpPost = new ActiveXObject (axName);		else {			var clsnames = new Array ("MSXML", "MSXML2", "MSXML3", "Microsoft");			for (n = 0; n < clsnames.length && httpPost == null; n++) {				axName = clsnames [n] + ".XMLHTTP";				try {					httpPost = new ActiveXObject (axName);				} catch (e) { axName = null; }			}			if (httpPost == null)				throw new Error ("XMLHTTP object could not be created.");		}		httpPost.onreadystatechange = function () { if (httpPost.readyState == 4) callback (httpPost); };	}		httpPost.open ("POST", url, true);	// async	httpPost.setRequestHeader ("Content-Type", "application/x-www-form-urlencoded");	setTimeout (function () { httpPost.send (data); }, 10);}
meta: 655	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/655/432952721b234d3c728df924ddce3eaac3b3cd89/callback.js/clean/mcs/class/System.Web/resources/callback.js