JS Lint is your friend in this case. It will log that * There's a missing semicolon on line 2 * There's a missing semicolon on line 3 * baz was being used be

JS Lint is your friend in this case. It will log that * There's a missing semicolon on line 2 * There's a missing semicolon on line 3 * baz was being used before it was defined. That's just in a global context. When it's in a function you get a little more: * the baz line is indented too far - because it's being interpreted as a new statement. Sure, you could eyeball your code looking for this. Or just use an automated tool that'd do it for you