classlist.addCLass code example

Example 1: javascript add class to element

var someElement= document.getElementById("myElement");
    someElement.className += " newclass";//add "newclass" to element (space in front is important)

Example 2: classList has class

if (document.body.classList.contains('thatClass')) {
    // do some stuff
}

Example 3: classlist

// use the classList API to remove and add classes
div.classList.remove("foo");
div.classList.add("anotherclass");

Example 4: add to classlist javascript

Add multiple classes to a <div> element:
document.getElementById("myDIV").classList.add("mystyle", "anotherClass", "thirdClass");

Remove a class from a <div> element:
document.getElementById("myDIV").classList.remove("mystyle");

Remove multiple classes from a <div> element:
document.getElementById("myDIV").classList.remove("mystyle", "anotherClass", "thirdClass");

Toggle between two classes for a <div> element:
document.getElementById("myDIV").classList.toggle("newClassName");

Find out if an element has a "mystyle" class:
document.getElementById("myDIV").classList.contains("mystyle");