111網頁前端設計工程師培訓班
	JavaScript  保留字
	
		
	
		
	
  JavaScript 的保留字 (reserved word) 包括關鍵字 (keyword) 、未來保留字 (future reserved word) 、三個字面常數 (literal) ,分別是 null 、 true 、 false 。
關鍵字為具有語法功能的標記,如下表
| break | delete | function | return | typeof | 
| case | do | if | switch | var | 
| catch | else | in | this | void | 
| continue | finally | instanceof | throw | while | 
| default | for | new | try | with | 
| let | 
未來保留字為將來有打算列入關鍵字之中的,如下表
| abstract | double | implements | private | throws | 
| boolean | enum | import | protected | transient | 
| byte | export | int | public | volatile | 
| char | extends | interface | short | |
| class | final | long | static | |
| const | float | native | super | |
| debugger | goto | package | synchronized |