Changing the background colour of an element using an ID selector

The following code is placed in the <head> section of the html file:


function changeColour(){
   document.getElementById("box").style.backgroundColor = "#B2D526";

function changeBack(){
   document.getElementById("box").style.backgroundColor = "#D5DEEA";


The above example uses two functions, one to make the change and one to change it back. This isn't the most efficient way of doing it but it is the simplest.

The object (element) you want to change is identified by an ID. Remember, this is unique to that object. In this example, the element containing the code above has been given the ID "box" and the opening tag looks like this: <pre id="box">.

The script is run by clicking a link. Here's the code:

<a href="javascript: changeColour()">Change colour</a>

Try the links below to see what happens.

Change colour | Change back

Note that the JavaScript code is placed "inline" i.e. within the anchor tag. Obviously, this is not ideal if we want to separate the behavioural layer from the structural layer.