28 May, 2009

Timing in JavaScript.

2009/07/02 Update:
I have created a far better version, which you can find here: [LINK]

"use strict";
var getTime = function (func, length) {
    var i, start, end;
    length = length || 1;
    start = new Date();
    for (i = 0; i < length; i += 1) {
    end = new Date();
    return end - start;

JavaScript does not have a built-in way to easily measure how long it takes to run code; however, it supplies the necessary building-blocks to create such a way.

You use getTime like this:

var time = getTime(function () {
    /* code goes here! */
}, 100000);

The variable time now contains how many milliseconds it took to run the function 100000 times.

  1. The first parameter should be a function. The time it takes to run this function is returned.
  2. The second parameter is how many times you want to run the function. The default is 1.

Using this function, you can easily see how long it takes to run chunks of code, which is useful in benchmarking.

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