Run results for: Different types of selecting

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/55.0.2883.87 Safari/537.36

Browser: Chrome 55

Operating system: Windows

Device Platform: Other

Date tested: 6 years ago

Test name	Executions per second
getElementById	306914.6 Ops/sec
querySelector("#id")	290923.1 Ops/sec
getElementsByClassName("class")[0]	301745.1 Ops/sec
querySelector(".class")	192167.2 Ops/sec
getElementById + getElementsByTagName	82686.9 Ops/sec
querySelectorAll("#id tag")	69106.6 Ops/sec
getElementById + getElementsByClassName[0]	285188.7 Ops/sec
querySelector("#id .class")	282789.3 Ops/sec
getElementsByClassName("class")	83912.9 Ops/sec
querySelectorAll(".class")	42237.8 Ops/sec

HTML Preparation code:

<div>
  <ul id="id1">
    <li class="c1">Element</li>
    <li id="id2" class="c1">Element</li>
    <li class="c1">Element</li>
    <li class="c1">Element</li>
  </ul>
</div>

Tests:

getElementById
document.getElementById("id2").innerHTML = "ciao"
querySelector("#id")
document.querySelector("#id2").innerHTML = "ciao"
getElementsByClassName("class")[0]
document.getElementsByClassName("c1")[0].innerHTML = "ciao"
querySelector(".class")
document.querySelector(".c1").innerHTML = "ciao"
getElementById + getElementsByTagName
var all = document.getElementById("id1").getElementsByTagName("li"); for (var i=0; i<all.length; i++) { all[i].innerHTML = "ciao"; }
querySelectorAll("#id tag")
var all = document.querySelectorAll("#id1 li"); for (var i=0; i<all.length; i++) { all[i].innerHTML = "ciao"; }
getElementById + getElementsByClassName[0]
document.getElementById("id1").getElementsByClassName("c1")[0].innerHTML = "ciao"
querySelector("#id .class")
document.querySelector("#id1 .c1").innerHTML = "ciao"
getElementsByClassName("class")
var all = document.getElementsByClassName("c1"); for (var i=0; i<all.length; i++) { all[i].innerHTML = "ciao"; }
querySelectorAll(".class")
var all = document.querySelectorAll(".c1"); for (var i=0; i<all.length; i++) { all[i].innerHTML = "ciao"; }

Run results for: Different types of selecting

getElementById

querySelector("#id")

getElementsByClassName("class")[0]

querySelector(".class")

getElementById + getElementsByTagName

querySelectorAll("#id tag")

getElementById + getElementsByClassName[0]

querySelector("#id .class")

getElementsByClassName("class")

querySelectorAll(".class")