- Element.classList
// Add class
el.classList.add("newClass");
// Remove class
el.classList.remove("foo");
// Check existence
el.classList.contains("foo");
// Toggle a class
el.classList.toggle("visible");
// replace class
el.classList.replace("foo", "bar")
https://developer.mozilla.org/en-US/docs/Web/API/Element/classList
- Class start with selector [class^=”pre-“]
- Only check the first item in classList
[class^="pre-"]
<div class="pre-foo foo"> -> true
<div class="foo pre-foo"> -> false