Much of the debugging process involves discovering where the bug is in the first place. Unfortunately, finding the little pests isn't always easy.
You can look for bugs in lots of different ways. This section covers some of your major options, from writing alerts into your code to using your browser's bug detector and other debugging tools.
Printing Variables with alert() Statements
The most tried-and-true debugging method is to use
alert() statements to print out what's going on in your script.
Figure 18-1 lists two functions. In one, if you enter random names in the prompt boxes, you'll see the greeting Ahoy, polloi! If you enter
Dave in the first prompt box and
Thau in the second one, you're supposed to get the message Howdy, partner! ...