Run results for: querySelector vs getElementById vs getElementsByClassName vs getElementsByTagName

Test name	Executions per second
✓ getElementsByClassName	4,380,357 Ops/sec
getElementsByTagName	4,360,594 Ops/sec
getElementById	4,264,977 Ops/sec
querySelector (tag)	1,278,573 Ops/sec
querySelector (id)	1,265,958 Ops/sec
querySelector (class)	1,210,884 Ops/sec

HTML Preparation code:

    <div class="test1">
        <div class="test1">
        <div class="test1"></div>
        <div class="test1"></div>
        <div class="test1">
            <div class="test1">
                <div class="test1"></div>
            </div>
        </div>
        <div class="test1"></div>
        <div class="test1"></div>
        </div>
        <div class="test1">
        <div class="test1"></div>
        <div class="test1">
            <div class="test1">
                <div class="test1"></div>
            </div>
        </div>
        <div class="test1">
            <div class="test1">
                <div class="test1"></div>
            </div>
        </div>
        <div class="test1"></div>
        </div>
        <div class="test1"></div>
        <div class="test1">
        <div class="test1"></div>
        <div class="test1">
            <div class="test1">
                <div class="test1"></div>
            </div>
            <div class="test1"></div>
        </div>
        <div class="test1"></div>
        <div class="test1"></div>
        <div class="test1"></div>
        </div>
        <div class="test1"></div>
        <div class="test1">
        <div class="test1">
            <div class="test1"></div>
            <div class="test1">
                <div class="test1">
                    <div class="test1">
                    <article class="test" id="test"></article>
                    </div>
                    <div class="test1">
                    <div class="test1"></div>
                    </div>
                    <div class="test1"></div>
                </div>
                <div class="test1"></div>
            </div>
        </div>
        <div class="test1"></div>
        <div class="test1"></div>
        </div>
        <div class="test1">
        <div class="test1"></div>
        <div class="test1">
            <div class="test1"></div>
            <div class="test1"></div>
        </div>
        <div class="test1"></div>
        <div class="test1"></div>
        <div class="test1"></div>
        </div>
    </div>

Tests:

getElementById
document.getElementById("test");
querySelector (id)
document.querySelector("#test")
getElementsByClassName
document.getElementsByClassName("test")
querySelector (class)
document.querySelector(".test")
getElementsByTagName
document.getElementsByTagName("test")
querySelector (tag)
document.querySelector("article")

Run results for: querySelector vs getElementById vs getElementsByClassName vs getElementsByTagName

getElementById

querySelector (id)

getElementsByClassName

querySelector (class)

getElementsByTagName

querySelector (tag)