Strictly removing and adding a class with the toggleClass method in jQuery

You can also pass a state parameter to toggleClass like true or false, then the class will either only be added or only removed.

Let's say we have the following CSS classes:

css.red {
  color: red;
}
  
.zzz {
  font-style: italic;
}

The paragraph class zzz is applied:

html<p class="zzz" id="test">text</p>
<button>click</button>

Let's just add the red class when clicked:

javascript$('button').click(function() {
  $('#test').toggleClass('red', true);
});

As you can see, pressing it again does not change anything.

All three listed methods for working with classes - addClass, removeClass, toggleClass can also take multiple classes as a parameter, and also allow applying a function to each element in the set.