How to get elements with multiple classes

Question

It's actually very similar to jQuery:

document.getElementsByClassName('class1 class2')

MDN Doc getElementsByClassName

AND (both classes)

var list = document.getElementsByClassName("class1 class2");
var list = document.querySelectorAll(".class1.class2");

OR (at least one class)

var list = document.querySelectorAll(".class1,.class2");

XOR (one class but not the other)

var list = document.querySelectorAll(".class1:not(.class2),.class2:not(.class1)");

NAND (not both classes)

var list = document.querySelectorAll(":not(.class1),:not(.class2)");

NOR (not any of the two classes)

var list = document.querySelectorAll(":not(.class1):not(.class2)");

querySelectorAll with standard class selectors also works for this.

document.querySelectorAll('.class1.class2');

As @filoxo said, you can use document.querySelectorAll.

If you know that there is only one element with the class you are looking for, or you are interested only in the first one, you can use:

document.querySelector('.class1.class2');

BTW, while .class1.class2 indicates an element with both classes, .class1 .class2 (notice the whitespace) indicates an hierarchy - and element with class class2 which is inside en element with class class1:

<div class='class1'>
  <div>
    <div class='class2'>
      :
      :

And if you want to force retrieving a direct child, use > sign (.class1 > .class2):

<div class='class1'>
  <div class='class2'>
    :
    :

For entire information about selectors:
https://www.w3schools.com/jquery/jquery_ref_selectors.asp

html

<h2 class="example example2">A heading with class="example"</h2>

javascritp code

var element = document.querySelectorAll(".example.example2");
element.style.backgroundColor = "green";

The querySelectorAll() method returns all elements in the document that matches a specified CSS selector(s), as a static NodeList object.

The NodeList object represents a collection of nodes. The nodes can be accessed by index numbers. The index starts at 0.

also learn more about https://www.w3schools.com/jsref/met_document_queryselectorall.asp

== Thank You ==