js保留的关键字
| break | else | new | var |
| case | finally | return | void |
| catch | for | switch | while |
| continue | function | this | with |
| default | if | throw | |
| delete | in | try | |
| do | instanceof | typeof |
还有一些关键字用于未来扩展语言功能的，也不建议用作js标识符
| abstract | enum | int | short |
| boolean | export | interface | static |
| byte | extends | long | super |
| char | final | native | synchronized |
| class | float | package | throws |
| const | goto | private | transient |
| debugger | implements | protected | volatile |
| double | import | public |
根据ECMAScript5,关键字 if、 super 和 public 可以用作对象的属性名，但鉴于其特殊性，不推荐使用。