I am listening on xhr.onprogress 
request.onprogress = function(e){
    return conf.progress ? conf.progress(e) : null;
};
where conf.progress is 
function(e){
    var position = e.position || e.loaded;
    var total = e.totalSize || e.total;
    var percent = ((e.loaded/e.total)*100)+"";
    console.log(percent);
    console.log(position, total);
    console.log(e);
}
percent yields wrong value in console like 2.789069431137492e-11 and this is what console.log(e) prints
XMLHttpRequestProgressEvent
    bubbles: false
    cancelBubble: false
    cancelable: true
    clipboardData: undefined
    currentTarget: undefined
    defaultPrevented: false
    eventPhase: 2
    lengthComputable: false
    loaded: 4982035
    position: 4982035
    returnValue: true
    srcElement: undefined
    target: undefined
    timeStamp: 1323097256269
    total: 18446744073709552000
    totalSize: 18446744073709552000
    type: "progress"
    __proto__: XMLHttpRequestProgressEvent
Why the e.totalSize: 18446744073709552000 is so big and even after the document is completely loaded e.loaded: 4982035 as totalSize should be equal to loaded when its complete