Style And Class
With JavaScript you can access and update an element’s style and even its class. Say that you have two CSS classes:
.warning {color: yellow;} .error {color: green;}
You can update or switch an element’s CSS class with the following JavaScript code:
var element = document.getElementById('element'); element.className = 'warning';
But you can access individual CSS attributes via an element’s style object, such as
var element = document.getElementById('element'); element.style.color = 'green';
Of course, you might update an element’s style based on some event or in conjunction of an Ajax call.