javascript 延迟执行

var lastIndex = 0;
var dvTest;
var timesTotal = 200000;
var lastDateTime = new Date().getTime();
window.onload = function(){
dvTest = document.getElementById("test");
TimerUpdater();
}

function TimerUpdater(){
var last = new Date().getTime();
while(lastIndex < timesTotal){
dvTest.innerHTML = lastIndex;
var now = new Date().getTime();
var t = now - last;
lastIndex++;

if(t > 100) break;
}

if(lastIndex >= timesTotal){
dvTest.innerHTML = new Date().getTime() - lastDateTime;
return;
}

setTimeout(TimerUpdater, 50);
}