Introduction to Pure Novice---Declaration specification for variable names

1. You can use a number, but you cannot start with a number

2. Can not use Chinese characters, of course, this is not the grammar requirements, is the customary requirements, (personally think: can use, but have not seen so use, because the pinyin has low to the human bottom line!) ）

3. Cannot use special symbols, underline and $ (personal opinion and JQ related)

4.js variables are strictly case-sensitive (individuals always use lowercase)

5. Declare variables to make sense, do not arbitrarily abcd (with ABCD I only saw Baidu that one so wayward)

6. Variable names cannot be duplicated with system keywords, reserved words (prevent keyword reserved word conflicts)

Introduction to Pure Novice---Declaration specification for variable names