---of JavaScript objects RegExp

1. Overview

A regular expression is an object that describes a character pattern.

Regular expressions are used to match string patterns and retrieve replacements;

2. Grammar

The former is a pattern and the latter is a modifier.

var New " XYZ " " I "  ); // equivalent to var reg =/xyz/i;

Note : When creating a regular object using the constructor, you need to precede the meta character with a backslash (\)

var New REGEXP ("\\w+"); // equivalent to var reg =/\w+/;

3. Modifier

I-----------  multi-line matching

4. Square brackets

Square brackets are used to find characters in a range.

[0-9] Find any number from 0 to 9 [a-z] find any character from A to Z [a-z] find any character from A to Z [a-z] find any character from A to Z [ADGK] 
     find any character within a given set [^adgk]   | Blue | Green) Find any of the options you specify

5, Meta-character

Characters that have special meanings

.          Any single character (other than line break) \w         Word character \w         non-word character \d         numeric character \d         non-numeric character \s         white space character \s         non-whitespace character \ n         line break \ r         Enter

6. quantifier

n+                 matches any string containing at least onen *                 matches any string n that contains 0 or more n?                 Match any string containing 0 or one n n{x}              to match the string containing the sequence of x N. N{x,} x is a positive integer. The preceding pattern n is matched at least X times consecutively. N{x,y} x and y are positive integers. The preceding pattern n appears consecutively at least X times, and matches at most Y times. n$    matches any string that ends with N. ^n   matches any string ending with N. =n
?! N        

---of JavaScript objects RegExp