Javascript tips

Use === to Test Equality
Include All Necessary Semicolons
Use JSLint
Use a Namespace
Avoid Using Eval
Use Decimals Cautiously
Start Blocks on the Same Line
Use Explicit Blocks
Declare All Variables First
Do Not Use "With"
Be Careful Using typeof
Treat parseInt With Care
Do Not Use Switch Fall Through
Avoid For...In Loops
Use Var to Declare Variables
Avoid Reserved / Special Words
Read Good Code

http://www.codeproject.com/Articles/580165/JavaScript-Best-Practices