Js--wiki

0. JS's basic data type

Boolean number String Array Object Null Undefined

1.

If the browser is disabled live does not support JS, then JS will not be attempted to execute, NoScript will be executed

<script><!--     ... // -</script>

<noscript> Your browser does not support JavaScript</noscript>

2. JavaScript is strictly case sensitive

3. \ code Line Wrapping

4. Variable names cannot start with a number

5. Variable (function) name preferably with hump or underline method

6. The string must be in the middle of the quotation marks

7.js \ r \ n \ t is not the same as HTML

8. Undefined indicates that the variable is not assigned a value, and null means that the variable is given a value that does not exist

9. Number.NaN

Number (' 123abc ') = = NaN;

parseint (' 123abc ') = = 123;

10. Force data Type Conversion Boolean (0) Number (' 123 ');

11. String concatenation Form

"+ A + B + x;

12. Shaping, floating-point types support self-increment, self-decrement operator--+ +

13.

Js--wiki