JAVASCRIPT

js classlist

classList.item(index); // Returns the item in the list by its index, or undefined if index is greater than or equal to the list's length
classList.contains(token); // Returns true if the list contains the given token, otherwise false.
classList.add(token1[, ...tokenN]); // Adds the specified token(s) to the list.
classList.remove(token1[, ...tokenN]); // Removes the specified token(s) from the list.
classList.replace(oldToken, newToken); // Replaces token with newToken.
classList.supports(token); // Returns true if a given token is in the associated attribute's supported tokens.
classList.toggle(token[, force]); // Removes token from the list if it exists, or adds token to the list if it doesn't. Returns a boolean indicating whether token is in the list after the operation.
classList.entries(); // Returns an iterator, allowing you to go through all key/value pairs contained in this object.
classList.forEach(callback[ ,thisArg]); // Executes a provided callback function once per DOMTokenList element.
classList.keys(); // Returns an iterator, allowing you to go through all keys of the key/value pairs contained in this object.
classList.values(); // Returns an iterator, allowing you to go through all values of the key/value pairs contained in this object.

JS classList

-- HTML --
<div class='container'></div>

-- JAVASCRIPT --
element.classList.contains('container'); // True or false
element.classList.add('my-class'); // Adds the class if it isn't present yet
element.classList.remove('my-class'); // Removes the class if it’s present
element.classList.toggle('my-class'); // Adds if not present, else removes

classlist.contain in javascript

let span = document.querySelector("span");
let classes = span.classList;
let result = classes.contains("d");
if (result) {
  span.textContent = "The classList contains 'c'";
} else {
   span.textContent = "The classList does not contain 'c'";
}

js classlist

// querySelector() - you can use element name / #id / .class
const varName = document.querySelector('div #idName .className');
// add class - classList.add()
varName.classList.add('someClassName'); // class name without the dot 
// remove class - classList.remove()
varName.classList.remove('someClassName');

classlist

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

values for classList

add() 		Adds one or more tokens to the list
contains() 	Returns true if the list contains a class
entries() 	Returns an Iterator with key/value pairs from the list
forEach() 	Executes a callback function for each token in the list
item() 		Returns the token at a specified index
keys() 		Returns an Iterator with the keys in the list
length 		Returns the number of tokens in the list
remove() 	Removes one or more tokens from the list
replace() 	Replaces a token in the list
supports() 	Returns true if a token is one of an attribute's supported tokens
toggle() 	Toggles between tokens in the list
value 		Returns the token list as a string
values() 	Returns an Iterator with the values in the list

.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', ... ]

classlist

classList.item(index);// Returns item in list by its index, or undefined if index >=list's length
classList.contains(token); // Returns true if list contains token, otherwise false.
classList.add(token1[, ...tokenN]); // Adds token to the list.
classList.remove(token1[, ...tokenN]); // Removes the token from the list.
classList.replace(oldToken, newToken); // Replaces token with newToken.
classList.supports(token); // Returns true if token is in associated attribute's supported tokens.
classList.toggle(token[, force]); // Removes token if it exists, or adds to list if it doesn't. Returns a boolean true if conteined, false otherwise.
classList.entries(); // Returns an iterator through all key/value pairs contained in this object.
classList.forEach(callback[ ,thisArg]); // Executes a provided callback function once per DOMTokenList element.
classList.keys(); // Returns an iterator through all keys of the key/value pairs contained in this object.
classList.values(); // Returns an iterator through all values of the key/value pairs contained in this object.