Text editors are very helpful in programming, providing tools and making it easier to understand the code. Open Text Wrangler on your computer and notice syntax highlighting and nifty tools.
If you're writing programs that will run online, a web browser will let you see what the end user will see. Open Safari for this exercise; then click Safari > Preferences > Advanced > Check show Develop Menu.
Debuggers are very helpful in following the execution of a program. There are many out there; at the moment, let's look at Safari's built-in "Web Inspector."