What are the relevant knowledge points of regular expressions in JavaScript

Xiaobian to share with you what are the relevant knowledge points of regular expressions in JavaScript, I believe most people still do not know how, so share this article for everyone's reference, I hope you have a lot of gains after reading this article, let's go to understand it together!

JavaScript regular expressions 1. Creating regular expressions

Literally. syntax: Reg = /pattern/modifiers; literal regularization consists of two positive oblique bars//, the first positive oblique bar followed by rules: /pattern[rules can write a variety of metacharacters| quantifier| character set| Assertion…] Write identifier/modifiers[g global match] after the second positive slant| i Ignore case| m-line matching| ^Starting position| $End Position] identifier.

var Reg = /box/gi;

Constructor. Syntax Reg = new RegExp( pattern , modifiers ); pattern, modifiers is a string in this case. What methods are created is the same, pattern templates, what to match, modifiers.

var Reg = new RegExp("box","gi");2.String Regular expression method description String.match(Reg) Returns an array containing all strings matched by RegExp or nullString.search(Reg) Returns the location of the first occurrence of a RegExp matching string String.replace(Reg, newStr) replaces the RegExp matching result with newStr and returns a new string String.split(Reg) Returns an array of strings split by the specified RegExp var str = 'a1b2c3a4a5', reg = /a/g;console.log(str.match(reg)); //["a", "a", "a"]var str = 'a1b2c3a4a5', reg = /a/;console.log(str.search(reg)); //0var str = 'a1b2c3a4a5', reg = /a/g;console.log(str.replace(reg,function(){ console.log(arguments); return 5555;}));var str = 'a,b,c,d', reg = /,/g; //console.log (str.split (',')); //["a", "b", "c", "d"]console.log(str.split(reg)) //["a", "b", "c", "d"]3.RegExp object's method method description RegExp.exec(String) Performs a match search in a string and returns an array of first matches RegExp.test(String) tests a pattern match in a string and returns true or false4. modifier

Modifiers, also called identifiers, specify matching patterns, modifiers are used to perform case sensitivity and global matching.

i Case matching ignored.

g matches globally, no g matches only the first element, no matching.

m Perform multi-row matching

var patt = /pattern/i; //ignore case matching var patt = /pattern/g; //global match var patt = /pattern/m; //perform multiline matching 5. metacharacters

A special character that has a special meaning in a regular expression.

Special translation characters. \ /。

. A single arbitrary character, except for newline\n and tab\r \escape characters, to escape symbols with special meaning to ordinary symbols: \.\ d Numeric [0~9]\D Non-numeric\s Space\S Non-space\w Character [Letter| digital| underscore]\W Non-character\b word boundary (except (word) alphanumeric_counts as word boundary) \B Non-word boundary var reg = /\./;// Match.var reg = /\\/;//Match\var reg = /\/;//Match/var str = '\\';var reg = /\\/g;console.log(reg.test(str)); //true The above is "What are the relevant knowledge points of regular expressions in JavaScript" All the contents of this article, thank you for reading! I believe that everyone has a certain understanding, hope to share the content to help everyone, if you still want to learn more knowledge, welcome to pay attention to the industry information channel!