JavaScript Switch Statement

The switch statement is used to perform different action based on different conditions.

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The JavaScript Switch Statement

Use the switch statement 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

Display today's weekday-name. Note that Sunday=0, Monday=1, Tuesday=2, etc:

var day=new Date().getDay();
switch (day)
{
case 0:
  x="Today is Sunday";
  break;
case 1:
  x="Today is Monday";
  break;
case 2:
  x="Today is Tuesday";
  break;
case 3:
  x="Today is Wednesday";
  break;
case 4:
  x="Today is Thursday";
  break;
case 5:
  x="Today is Friday";
  break;
case 6:
  x="Today is Saturday";
  break;
}

The result of x will be:

Today is Monday

The default Keyword

Use the default keyword to specify what to do if there is no match:

Example

If the day is NOT Saturday or Sunday, then write a default message:

var day=new Date().getDay();
switch (day)
{
case 6:
  x="Today is Saturday";
  break;
case 0:
  x="Today is Sunday";
  break;
default:
  x="Looking forward to the Weekend";
}

The result of x will be:

Looking forward to the Weekend