The JavaScript language sets aside certain words that you cannot use as the names of variables, functions, methods, or objects. Some of these words are currently used by JavaScript; others are reserved for future use.
The reserved words are
| finally | protected | |
| abstract | float | public |
| Boolean | for | return |
| break | function | short |
| byte | goto | static |
| case | if | super |
| catch | implements | switch |
| char | import | synchronized |
| class | in | this |
| const | instanceof | throw |
| continue | int | throws |
| default | interface | transient |
| do | long | true |
| double | native | try |
| else | new | var |
| extends | null | void |
| false | package | while |
| final | private | with |