javascript - Measure ajax receive time -

i'm trying measure download/upload speed , make lot of simultaneous ajax requests. of them blocked due browser connections limit, can't establish real download time doing kind of this:

var start = new date; $.get('/data').done(function () {     console.log(new date - start); }); 

so, i'm using raw xhr way:

var open, start, end; var req = new xmlhttprequest(); req.open('get', '/data', true); req.onreadystatechange = function () {     switch (this.readystate) {         case 2:         case 3:             if (!start) { start = new date(); }             break;         case 4:             if (!end) { end = new date(); }             console.log('%d: pending = %d, download = %d, total = %d', i, start - open, end - start, end - open);             break;     } }; if (!open) { open = new date(); } req.send(); 

is there way same using jquery?

update

i need initialize start not before ajax request, after requeststate changed 2 or 3 (actually downloading/uploading).

update #2

there's related issue in jquery bugtracker: http://bugs.jquery.com/ticket/9883

$.ajaxprefilter(function( options, originaloptions, jqxhr ) {     if ( options.onreadystatechange ) {         var xhrfactory = options.xhr;         options.xhr = function() {             var xhr = xhrfactory.apply( this, arguments );             function handler() {                 options.onreadystatechange( xhr, jqxhr );             }             if ( xhr.addeventlistener ) {                 xhr.addeventlistener( "readystatechange", handler, false );             } else {                 settimeout( function() {                     var internal = xhr.onreadystatechange;                     if ( internal ) {                         xhr.onreadystatechange = function() {                             handler();                             internal.apply( this, arguments );                          };                     }                 }, 0 );             }             return xhr;         };     } });      var start = null; var xhr = $.ajax({    url: "/data",    complete: function() {       var end = new date().gettime();       var requesttime = end - start;       console.log(requesttime);    }    onreadystatechange: function(xhr) {       if(xhr.readystate == 3 && start == null) {          start = new date().gettime();       }    } }); 

using jquery.ajax() method complete callback fires on success or error (after callbacks... use individual callbacks if want make use of those).

update (see comment): using code sourced here: https://gist.github.com/chrishow/3023092 utilising .ajaxprefilter() method can add onreadystatechange option .ajax() method.