$.ajax async:false doesn't work in IE and Firefox, works in Chrome/Safari

[ahmetsan]

I am trying to measure download speed with ajax call. Here is the my code

var start = new Date();
$.ajax ({
    url: 'https://www.example.com/perftest/dummyFile1024',
    cache: false,  
    success : function() {
        var total = (new Date() - start)
        alert(total)    
    },
    error : function(jqxhr, status, ex) {}
})

It doesn't wait until whole file loaded. When I add async: false, it waits for loading whole file and I am able to measure bandwidth at chrome and safari however internet explorer and firefox still works the same as async: true, they don't wait until whole file loaded. Do you have any idea how I can manage it works for I.E. and firefox as well? Thanks.

[gits]

i assume that you use jQuery?

http://api.jquery.com/jQuery.ajax/

is it a xdomain-request? or is the dataType jsonp?