Run results for: querySelectorAll vs. querySelector + querySelectorAll vs. getElementById + querySelectorAll

Run details:

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/142.0.0.0 Safari/537.36

Browser: Chrome 142

Operating system: Linux

Device Platform: Desktop

Date tested: 7 months ago

getElementById + querySelectorAll

854K/s

querySelector + querySelectorAll

786K/s

querySelectorAll

538K/s

View exact numbers

Test name	Executions per second
✓ getElementById + querySelectorAll	853,564 Ops/sec
querySelector + querySelectorAll	785,615 Ops/sec
querySelectorAll	537,534 Ops/sec

HTML Preparation code:

<div id="someId">
    <div class="someClass"></div>
    <div class="someClass"></div>
    <div class="someClass"></div>
    <div class="someClass"></div>
    <div class="someClass"></div>
    <div class="someClass"></div>
    <div class="someClass"></div>
    <div class="someClass"></div>
    <div class="someClass"></div>
    <div class="someClass"></div>
</div>
<div>
    <div class="someClass"></div>
    <div class="someClass"></div>
    <div class="someClass"></div>
    <div class="someClass"></div>
    <div class="someClass"></div>
    <div class="someClass"></div>
    <div class="someClass"></div>
    <div class="someClass"></div>
    <div class="someClass"></div>
    <div class="someClass"></div>
</div>

Tests:

querySelectorAll
const matches = document.querySelectorAll('#someId .someClass'); matches.forEach(() => {});
querySelector + querySelectorAll
const matches = document.querySelector('#someId').querySelectorAll('.someClass'); matches.forEach(() => {});
getElementById + querySelectorAll
const matches = document.getElementById('someId').querySelectorAll('.someClass'); matches.forEach(() => {});