From http://www.w3schools.com (Copyright Refsnes Data)

JavaScript Switch Statement

Conditional statements in JavaScript are used to perform different actions based on different conditions.

Examples

Switch statement
How to write a switch statement.

The JavaScript Switch Statement

You should use the switch statement if you want to select one of many blocks of code to be executed.

Syntax

switch(n)
{
case 1:
  execute code block 1
  break;    
case 2:
  execute code block 2
  break;
default:
  code to be executed if n is
  different from case 1 and 2
}

This is how it works: First we have a single expression n (most often a variable), that is evaluated once. The value of the expression is then compared with the values for each case in the structure. If there is a match, the block of code associated with that case is executed. Use break to prevent the code from running into the next case automatically.

Example

<script type="text/javascript">
//You will receive a different greeting based
//on what day it is. Note that Sunday=0,
//Monday=1, Tuesday=2, etc.

var d=new Date();
theDay=d.getDay();
switch (theDay)
{
case 5:
  document.write("Finally Friday");
  break;
case 6:
  document.write("Super Saturday");
  break;
case 0:
  document.write("Sleepy Sunday");
  break;
default:
  document.write("I'm looking forward to this weekend!");
}
</script>