ID abd Class

ID's are unique

• Each element can have only one ID
• Each page can have only one element with that ID

Classes are NOT unique

• You can use the same class on multiple elements.
• You can use multiple classes on the same element.

ID's have special browser functionality

If you have a URL like http://yourdomain.com#comments, the browser will attempt to locate the element with an ID of "comments" and will automatically scroll the page to show that element. It is important to note here that the browser will scroll whatever element it needs to in order to show that element, so if you did something special like a scrollable DIV area within your regular body, that div will be scrolled too.