JavaScript: Reserved Words

JavaScript has a number of reserved words that you cannot use as identifiers. Reserved words have a specific meaning to the JavaScript language, as they are part of the language syntax. Using a reserved word causes a compilation error when loading your script.

List of Reserved words

- break    - default    - function    - return    - var        - case
- delete   - if         - switch      - void      - catch      - do
- in       - this       - while       - const     - else       - instanceof
- throw    - with       - continue    - finally   - let        - try    
- for,     - new        - debugger

JavaScript also has a list of future reserved words. These words are not currently part of the JavaScript language, although they are reserved for future use.

Original source and more info:
http://msdn.microsoft.com/en-us/library/hh699851(v=vs.94).aspx