Decisions and Loops - Beginning JavaScript - page 75

Finally, the fourth and fifth case statements output a message that the number the user has entered is
too high:
case 4:
document.write("Too high!");
break;
You do need to add a default case in this example, because the user might very well (despite the
instructions) enter a number that is not between 1 and 5 , or even perhaps a letter. In this case, you add
a message to let the user know that there is a problem:
default:
document.write("You did not enter a number between 1 and 5.");
break;
A default statement is also very useful for picking up bugs—if you have coded some of the case
statements incorrectly, you will pick that up very quickly if you see the default code being run when it
shouldn't be.
Finally, you have added the closing brace indicating the end of the switch statement. After this you
output a line to indicate where the execution continues:
}
document.write("<br />Execution continues here");
Note that each case statement ends with a break statement. This is important to ensure that execution
of the code moves to the line after the end of the switch statement. If you forget to include this, you
could end up executing the code for each case following the case that matches.
executing the Same Code for Different Cases
You may have spotted a problem with the switch statement in this example—you want to execute
the same code if the user enters a 1 or a 2 , and the same code for a 4 or a 5 . However, to achieve
this, you have had to repeat the code in each case. What you want is an easier way of getting
JavaScript to execute the same code for different cases. Well, that's easy! Simply change the code so
that it looks like this:
switch (secretNumber) {
case 1:
case 2:
document.write("Too low!");
break;
case 3:
document.write("You guessed the secret number!");
break;
case 4:
case 5:
document.write("Too high!");