Web Design in a Nutshell, 3rd Edition

Control Structures

There are numerous control structures available to you in JavaScript. They are broken up into a few broad categories: conditionals, loops, switches, and functions.

On alert

alert is a helpful tool for alerting you to certain events occurring in your code. It creates a little dialog box with whatever statement you passed, along with an “OK” button that you can use to close it.

alert( 'send this message' );

For times when you only want a little information, this can be very helpful, but if you are calling alert many times throughout a large script, it can get a little frustrating to have to close each of the dialog boxes as they appear. Several tools have been developed to aid in JavaScript debugging that assist you in outputting information to the screen without using alert( ). On the simple end, there is jsTrace (http://www.easy-designs.net/code/jsTrace/), a port of the ActionScript trace window, and for more robust debugging, there is fvLogger (http://www.alistapart.com/articles/jslogging), which is very similar to the JavaScript Console that comes with most Mozilla-based browsers and Opera.