Javascript: What is the fastest way to click an element a million times

Question

I'm doing this fun coding challenge that I found at a meetup (doyouevendev.org)

What is the fastest way to generate a million clicks on an element? The coding challenge seems to be centred around the inspector, which I'm finding worthwhile.

My code (that i'm executing in chrome command line):

var item = document.getElementsByClassName("clicky-button pulse");
var item = item[0];
count = 0;
(function clickIt() {
    count += 1
    setInterval(function changeClicks() {
        item.click();
    }, 1);
    if (count <= 50) {
        clickIt();
    };
})();

I suspect there's a better way... It actually seems to be slowing down...

"What is the fastest way to click an element a million times" - get a LOT of interns :) — max, Feb 18 '16 at 19:25
do you mean set up web workers or something similar? @ViktorDanilov — Zach Smith, Feb 18 '16 at 19:27
Can't you just use a `for` loop? `for (var i = 0; i < 1e6; i++) { item.click(); }`. JS doesn't have threads and, as was pointed out, workers can't access the DOM. — Mike Cluck, Feb 18 '16 at 19:30
I've completed the game and actually clicking it isn't the way to beat that level. The instructions even tell you not to. — darryn.ten, Feb 20 '16 at 10:50
Yeah I found it. Now in stuck in level 3.this is partly because I don't really understand the concept of sockets, frames, ddp, etc. Do you have any helpful hints? — Zach Smith, Feb 20 '16 at 12:32
@darryn.ten - yes, but changing the value to 1 000 000 didn't do anything. which is why i resorted to this, before trying 999 999 + 1 click — Zach Smith, Jun 29 '17 at 21:59

score 15 · Accepted Answer · edited May 23 '17 at 12:02

15

The 'negative' while loop should be slightly faster:

var i = 1000001;
while (--i) {
   item.click();
}

Choose one: http://www.stoimen.com/blog/2012/01/24/javascript-performance-for-vs-while/

Javascript Performance: While vs For Loops

edited May 23 '17 at 12:02

Community

1
1

answered Feb 18 '16 at 19:31

RomanPerekhrest

88,541
4
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which is more efficient? a while loop or a for loop? – Zach Smith Feb 18 '16 at 19:35
http://moduscreate.com/javascript-performance-tips-tricks/ – Viktor Feb 18 '16 at 19:37
https://jsperf.com/compare-while-loop-vs-for-loop/4 – max Feb 18 '16 at 19:44
@max, good test. I prefer to use "for/while chached". We should store an array length into a variable to avoid array length evaluation on every loop iteration – RomanPerekhrest Feb 18 '16 at 19:54
I'm actually getting that the "reverse while" is 33% slower than the "basic while" on chrome. Too bad JSPerf is so broken that you can't see the results in other browsers. – max Feb 18 '16 at 20:00
@max, of course, among various browsers the results may differ – RomanPerekhrest Feb 18 '16 at 20:02

Jonathan.Brink · Answer 2 · 2016-02-18T19:45:43.527

5

JavaScript is single-threaded so keep it simple:

for (var i = 0; i < 1000000; i++) {
    item.click();
}

EDIT: Looks like @romanperekhrest's answer may be slightly faster since it's using a decrementing while loop.

edited Feb 18 '16 at 19:45

answered Feb 18 '16 at 19:30

Jonathan.Brink

23,757
20
73
115

meh. looks like this crashed the site – Zach Smith Feb 18 '16 at 19:44

Javascript: What is the fastest way to click an element a million times

2 Answers2