rem: req.addErrback(callback); req.addCallback(callback); 
add: qaTools.httpPostRequest(litmus.baseURL+'json.cgi', qs, callback); 
context: 	validateLogin : function(uname, passwd, callback) {	    var req = doSimpleXMLHttpRequest(litmus.baseURL+'json.cgi', {	       validate_login: 1,	       username: uname,	       password: passwd	    });	    req.addErrback(callback);	    req.addCallback(callback);	},
meta: 8395	/local1/tlutelli/issta_data/temp/all_js/javascript/2007_temp/2007/8395/80c899c30598ba2881a5824f4f4f5f0118cc5392/litmus.js/clean/testing/extensions/community/chrome/content/litmus.js