在javascript中，根据规定，关键字是保留的，不能用作变量名或函数名。
| break | delete | function | return | type |
|---|---|---|---|---|
| case | do | if | switch | var |
| catch | else | in | this | void |
| continue | finally | instance of | throw | while |
| default | for | new | try | with |
保留字在某种意义上是为将来的关键字而保留的单词。因此保留字不能被用作变量名或函数名。
| abstract | debugger | final | int | private | super |
|---|---|---|---|---|---|
| boolean | double | float | interface | protected | synchronize |
| byte | enum | goto | long | public | throws |
| char | export | implements | native | short | transient |
| class | extends | import | package | static | volatile，const |