Changing an Element’s Class with JavaScript: Simple and Modern Techniques

In JavaScript, modifying the CSS classes of HTML elements allows for dynamic styling changes based on user interactions or other events. Changing classes is especially useful for toggling visibility, updating themes, or applying specific effects. Here’s a look at different ways to change an element’s class with JavaScript, from basic to more advanced techniques.

1. Directly Setting the className Property

The simplest way to change an element’s class is to use the className property. This approach overrides any existing classes, so it’s best used when you want to replace the current class entirely.

document.getElementById("myElement").className = "newClass";

This method sets the class to "newClass" on the specified element. For multiple classes, you can provide a space-separated list:

document.getElementById("myElement").className = "class1 class2";

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