JavaScript Console Measuring time - console.time()


console.time() can be used to measure how long a task in your code takes to run.

Calling console.time([label]) starts a new timer. When console.timeEnd([label]) is called, the elapsed time, in milliseconds, since the original .time() call is calculated and logged. Because of this behavior, you can call .timeEnd() multiple times with the same label to log the elapsed time since the original .time() call was made.

Example 1:

console.time('response in');

alert('Click to continue');
console.timeEnd('response in');

alert('One more time');
console.timeEnd('response in');

will output:

response in: 774.967ms
response in: 1402.199ms

Example 2:

var elms = document.getElementsByTagName('*'); //select all elements on the page

console.time('Loop time');

for (var i = 0; i < 5000; i++) {
    for (var j = 0, length = elms.length; j < length; j++) {
        // nothing to do ...

console.timeEnd('Loop time');

will output:

Loop time: 40.716ms