Naming
Names allow to identify variables, functions, types, labels and properties of objects. Rules for naming:
- first character may be one of A-Z, a-z, underscore _, or dollar sign $
- subsequent characters may be one of 0-9, A-Z, a-z, underscore _, or dollar sign $
- names are case sensitive, for example x and X are different variables
- name must not match the reserved word
You should also avoid using the name of
- JavaScript built-in objects, properties, and methods
- some Java objects and properties as JavaScript identifiers
- some Java objects and properties as JavaScript identifiers
- HTML and Window objects and properties
Reserved words
| abstract | arguments | await* | boolean |
| break | byte | case | catch |
| char | class* | const | continue |
| debugger | default | delete | do |
| double | else | enum* | eval |
| export* | extends* | false | final |
| finally | float | for | function |
| goto | if | implements | import* |
| in | instanceof | int | interface |
| let* | long | native | new |
| null | package | private | protected |
| public | return | short | static |
| super* | switch | synchronized | this |
| throw | throws | transient | true |
| try | typeof | var | void |
| volatile | while | with | yield |
Words marked with* are new in ECMAScript 5/6.
ECMAScript 5/6 does not have full support in all browsers.