Javascript Add Class

Michael Zippo 04.11.2021

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Adding a class property to an element helps the developer to create a dynamic user experience on the web page. When a class property is added to an element, that selected element will take on the style associated with that class name.

Think of a user by clicking a button. When the button is clicked, we want a section of the webpage to change according to our CSS stylesheet. You can assign a class name associated with this style to the element to change its appearance after clicking on the button.

Creating an interactive experience is important in all front-end programming. In this guide, we’ll explore two ways to add a class name to a selected element in plain JavaScript. Eventually, you will be able to use this tool in your projects.

How to use JavaScript Add Class

In JavaScript, adding a class name can be done in two ways. First, we will select the desired HTML element. Then we have the option to use the className or add () property to add the name of the class to the element. We will go through the syntax and use it in the next section.

Remember , we are using simple JavaScript here. No libraries are needed. As we use JavaScript regularly, it is a common practice to wrap the above logic in a function and pass that function to an event handler. This will ensure that the function to add the class name only occurs after a specific event has taken place.

As for HTML elements, they can have multiple class names. This is helpful to remember that we can add class names to elements that already have other class names or IDs. All we need to keep in mind is that the style is associated with which the class names in our project and add the names to the elements we want to apply the style.

JavaScript syntax for adding a class name

We will see two ways to add a class name to an element. Remember the previous section that wrapping up the logic of adding a class interior to a function is common practice. once we have created our function, we can call it inside the onClick HTML attribute. The first way to add a class name using simple javascript is through the className property. the logic is here to select the item, then call .className on the selected item. then we can concatenate the class name to the element.

Let start with our HTML Code:

using method JavaScript onClick , we can call our function after clicking on the button. LET’S TRY by clicking on the button.

To review what just happened, we added the class name "background" which was associated with the style in our CSS file. After creating a JavaScript function to find the element and append the class name, the class style was applied to the

We always get the now has the "background" class added. & Nbsp;