JSFiddle - React, Tailwind, and code Playground
by ult_combo
HTML
<input type="checkbox" />
<input type="checkbox" />
<input type="checkbox" />
<input type="checkbox" />
<input type="checkbox" />
JavaScript
var a = document.querySelectorAll('input[type="checkbox"]');
for (var i=0; i<a.length; i++)
a[i].checked = true;