getElementById vs. querySelector

JavaScript performance comparison

Revision 32 of this test case created

Info

Compare the speed of getElementById to querySelector

Preparation code

<p id="foo">Foo</p>
<p id="bar">Bar</p>
<p id="baz">Baz</p>

<p class="test">Baz</p>

<p class="test">Baz</p>
<p class="test">Baz</p>


<p class="test">Baz</p>
<script>
Benchmark.prototype.setup = function() {
    var select = function(name)
    {
        var o = name.charAt(0);
        if      (o == '#') return document.getElementById(name.substr(1, name.length -1));
        else if (o == '.') return document.getElementsByClassName(name.substr(1, name.length -1));  
        else               return document.getElementsByTagName(name);
    };
};
</script>

Preparation code output

Foo

Bar

Baz

Baz

Baz

Baz

Baz

Test runner

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Testing in unknown unknown
Test Ops/sec
getElementById
var bar = document.getElementsByClassName(".test");
pending…
querySelector
var bar = document.querySelectorAll(".test");
pending…
mapping to getElementById
var bar = select(".test");
pending…

Compare results of other browsers

Revisions

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