Regular expressions in JavaScript

How to create

var reg=/\s/var reg=New RegExp ('\\s')//need to be escaped

Matching principle

All letters and numbers are matched by literal means

Special symbols need to be escaped with a backslash (\) as a prefix

Match character

[...] Match any of the characters in parentheses

[^...] ^ as the first character in the left parenthesis, for example: [^ABC] means all characters except A,b,c

\w equivalent to [a-za-z0-9] \w equivalent to [^a-za-z0-9]

\s any Unicode whitespace character \s non-whitespace

\d any ASCII number, equivalent to [0-9] \d takes a character other than 0-9

[\b] backspace direct volume

Multiple matches

{N,m} matches the number of occurrences of the previous item , greater than or equal to n, less than or equal to M

{n} matches n times

{N,} matches at least n times

？ Equivalent to {0,1}

+ equivalent to {1,}

* Equivalent to {0,}

Specify a matching location

^ Start of matching string

$ match End of string

\s matches the word boundary, \s the opposite, for example:

The (? =p) 0 wide forward assertion requires that the next characters all match p (?! p) on the contrary

Modifier

At the end/outside

I pattern matching is case insensitive

G Global Match

M multi-line pattern matching, example:

Select, sublet, quote

| Select modifier, match left to right by expression, match to left, right mismatch

(...) combinations, combining several items into 1 units, which can be referenced by \ n (?...) Group only, do not participate in references, can refer to return results

\ n used to refer to the previous (... ) matches

Regular expressions in JavaScript