Created by Jerry Wang, last modified on Sep 27, 2014
<html>
<script>
function process() {
var arra = [];
var count = 900000;
for( var i = 0; i < count; i++) {
arra[i] = i;
}
console.log("array length: " + arra.length);
}
var start = +new Date();
console.time("insert array");
process();
var end = +new Date();
console.timeEnd("insert array");
console.log("time spent: " + ( end - start));
</script>
</html> 在function process内，实现填充一个很大的array。如果需要计算填充指定数目的array所花费的毫秒数，方法1可以通过在call function之前和之后手动取两个时间点的时间戳，做差即可。
另一种方法是用Chrome自带的console.time,这种办法求出的执行时间更准确:
![主流浏览器四大综合性能测试[图]](data:image/gif;base64,R0lGODlhAQABAIAAAP///wAAACwAAAAAAQABAAACAkQBADs=)