JavaScript FAQ

Answers to Questions about...
Troubleshooting JavaScript/JScript

3. What are the most common scripting mistakes?

In his excellent JavaScript Sourcebook, in a section that begins, "We're only human, after all, and making misteaks is part of our nature," Gordon McComb identifies eleven common JavaScript gaffs:

• Omitting quotation marks in Strings
• Mismatched quotation mark types (' and ")
• Omitting quotation marks when comparing strings
• Confusing '=' (assign) and '==' (compare)
• Improperly nested blocks in IF-THEN-ELSE statements
• Trying to write to the script document
• Trying to access forms as a property of a window rather than a document
• Using String methods with the wrong objects
• Endless loops lock up the browser
• Missing or mismatched '{' or '}' around blocks
• Omitting the return() statement in a function