Switch Statement in Javascript.

Using switch Statement.

• A swich statement has the form:

    switch (expression) {
      case (expression1): // Start here if expression == expression1
        statement;
        break;            // Jump outof switch statement
      case (expression2): // Start here if expression == expression2
        statement;
        break;            // Jump outof switch statement
      case (expression3): // Start here if expression == expression3  
        statement;
        break;            // Jump outof switch statement
      default:            // Start here if No match        
        statement;
    }

  
  Where :
  • Expression is any legal Javascript expression that that returns a value.
  • Statements are any legal Javascript statements or block of statements that is been evaluated.
  • If one of the case expessions matches the swicth expression, program execution jumps to those statements and continues to the end of the switch block unless a break statement is encountered, which ends the switch block.
  • If nothing matches, execution branches to the optional default statement.
  • If no default exists and no matching case expression exist, execution falls through the switch statement and the statement ends.

  <script type="text/javascript">
    var sum=prompt("Enter a hole number; 1,2 or 3");
    switch (sum) {
      case '1': // Start here if expression == expression1
        document.write("Number is exact 1");
        break;            // Jump outof switch statement
      case '2': // Start here if expression == expression2
        document.write("Number is exact 2");
        break;            // Jump outof switch statement
      case '3': // Start here if expression == expression3
        document.write("Number is exact 3");
        break;            // Jump outof switch statement
      default:            // Start here if No match
        document.write("The number is not valid!");
    }
  </script>