JavaScript: Changing a Element's Style

Xah Lee, 2006-02-28, …, 2013-04-27

This page shows a example of how to change a element's style with JavaScript.

Sample

Press the following buttons to change the color.

Color Me RED BLUE

Code

Here's the HTML code:

<p>
<span id="id13959">Color Me</span>
<button id="b1">RED</button>
<button id="b2">BLUE</button>
</p>

Here's the JavaScript code:

var xx = document.getElementById("id13959");
var button1 = document.getElementById("b1");
var button2 = document.getElementById("b2");

button1.addEventListener("click", function () {xx.style.color="red";} , false);
button2.addEventListener("click", function () {xx.style.color="blue";} , false);

This technique can be used to change the CSS value for any HTML element. All you need to do is to give the HTML tag a “id”, and define in JavaScript when should the change happen.

CSS Property Names in JavaScript

In general, if your CSS attribute is “some-thing”, the JavaScript's attribute name should be like this: ‹ele›.style.someThing="value". Example:

Pseudo Selectors Cannot be Scripted

CSS's pseudo selectors (⁖ a:visited, a:link, div.nav:before, div.nav:first-child) cannot be scripted. You can use JavaScript to script the CSS source code itself, but that is not widely supported.

2011-01-12 thanks to NTTalex for a correction.