What is the difference between id and class in CSS, and when should I use them? [duplicate]

Answer 1

For more info on this click here.

Example

Text

#header_id {font-color:#fff}
.header_class {font-color:#000}

(Note that CSS uses the prefix # for IDs and . for Classes.)

However color was an HTML 4.01 tag attribute deprecated in HTML 5. In CSS there is no "font-color", the style is color so the above should read:

Example

Text

#header_id {color:#fff}
.header_class {color:#000}

The text would be white.