CSS Id vs Class

ID is unique
    * Each element has only one ID
    * Each page has only one element with that ID
    * Defined with “#”

Example

#myid
{
text-align:center;
color:red;
}

Classes is NOT unique
    * The same class can be used on multiple elements.
    * Multiple classes can be used on the same element.
    * Defined with “.”

Example

.center {text-align:center;}

OR

div.center {text-align:center;}