Run results for: getBoundingClientRect vs style

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/112.0.0.0 Safari/537.36

Browser: Chrome 112

Operating system: Mac OS X 10.15.7

Device Platform: Desktop

Date tested: one year ago

Test name	Executions per second
getBoundingClientRect fn 100	2721.6 Ops/sec
get inline style 100	3414.3 Ops/sec
getBoundingClientRect fn 10000	28.4 Ops/sec
get inline style 10000	34.4 Ops/sec
getBoundingClientRect fn 1000000	0.3 Ops/sec
get inline style 1000000	0.3 Ops/sec

HTML Preparation code:

<div id='box' style="width: 331px;">test box</div>

Script Preparation code:

let width = 311;

setInterval(() => {
    const box = document.getElementById('box');
    width += 10;
    box.style.width = width;
}, 100);

Tests:

getBoundingClientRect fn 100
const t0 = performance.now(); for (let i = 0; i < 100; i++){ const width = document.getElementById('box').getBoundingClientRect().width; console.log(width); } const t1 = performance.now(); console.log(`${t1 - t0} ms`);
get inline style 100
const t0 = performance.now(); for (let i = 0; i < 100; i++){ const width = Number(document.getElementById('box').style.width.replace('px', '')); console.log(width); } const t1 = performance.now(); console.log(`${t1 - t0} ms`);
getBoundingClientRect fn 10000
const t0 = performance.now(); for (let i = 0; i < 10000; i++){ const width = document.getElementById('box').getBoundingClientRect().width; console.log(width); } const t1 = performance.now(); console.log(`${t1 - t0} ms`);
get inline style 10000
const t0 = performance.now(); for (let i = 0; i < 10000; i++){ const width = Number(document.getElementById('box').style.width.replace('px', '')); console.log(width); } const t1 = performance.now(); console.log(`${t1 - t0} ms`);
getBoundingClientRect fn 1000000
const t0 = performance.now(); for (let i = 0; i < 1000000; i++){ const width = document.getElementById('box').getBoundingClientRect().width; console.log(width); } const t1 = performance.now(); console.log(`${t1 - t0} ms`);
get inline style 1000000
const t0 = performance.now(); for (let i = 0; i < 1000000; i++){ const width = Number(document.getElementById('box').style.width.replace('px', '')); console.log(width); } const t1 = performance.now(); console.log(`${t1 - t0} ms`);

Run results for: getBoundingClientRect vs style

getBoundingClientRect fn 100

get inline style 100

getBoundingClientRect fn 10000

get inline style 10000

getBoundingClientRect fn 1000000

get inline style 1000000