how to get class name of div in javascript code example

Example 1: javascript get class name

document.getElementById("myDIV").className = "mystyle";

Example 2: how get class name

String className = this.getClass().getSimpleName();

Example 3: classnames javascri+t

Installation:
yarn add classnames or npm i classnames

Usage:
classNames('foo', 'bar'); // => 'foo bar'
classNames('foo', { bar: true }); // => 'foo bar'
classNames({ 'foo-bar': true }); // => 'foo-bar'
classNames({ 'foo-bar': false }); // => ''
classNames({ foo: true }, { bar: true }); // => 'foo bar'
classNames({ foo: true, bar: true }); // => 'foo bar'
 
// lots of arguments of various types
classNames('foo', { bar: true, duck: false }, 'baz', { quux: true }); // => 'foo bar baz quux'
 
// other falsy values are just ignored
classNames(null, false, 'bar', undefined, 0, 1, { baz: null }, ''); // => 'bar 1'

TypeInstallation:
yarn add @types/classnames