class list methods javascript code example

Example 1: add to classlist javascript

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

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

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

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

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

Example 2: javascript list class properties

function getClassProperties(instanceOfClass) {
  const proto = Object.getPrototypeOf(instanceOfClass);
  const names = Object.getOwnPropertyNames(proto);
  return names.filter(name => name != 'constructor');
}

Example 3: .classList

// .classList method returns an array of the classes attached to the element it is called with.
document.getElementById("myDIV").classList
// It returns
// [ 'className1', 'className2', ... ]