JSFiddle - React, Tailwind, and code Playground

HTML

<div>text</div>
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<div>text</div>
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<section id="container">
    <header id="1">
        <span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span>
    </header>
    <article id="2">
       ...

JavaScript

var
    time1,time2,start1,start2;
start1=new Date();
    for(var i=10000;i!==0;i--)
        document.querySelectorAll('#container header,#container article,#container footer').length;
time1=new Date()-start1;

start2=new Date();
    for(var i=10000;i!==0;i--)
        document.querySelectorAll('#container>*').length;
time2=new Date()-start2;

alert(time1<time2?'lampslave прав на все '+(time2-time1)+'мс':(time2<time1?'Serator прав на все '+(time1-time2)+'мс':'Ничья!'));