How to use regular expressions in javascript

This article mainly introduces how to use regular expressions in Javascript. it is very detailed and contains simple examples. we recommend this article to you. Usage

1. create an expression

Method for creating a regular expression class in JavaScript:

Var regex = new RegExp ("\ d {5}") or 2.var regex =/\ d {5}/(recommended)

/Expression/is the syntax provided by JavaScript to simplify the preparation of regular expressions. the regular expressions written in // do not need to be escaped.

RegExp object method:

2. determine whether a match exists.

Test (str) checks whether the string str matches a regular expression, which is equivalent to IsMatch.

The code is as follows:

Var regex =/. + @. + /;
Alert (regex. test ("a@ B .com "));
Alert (regex. test ("AB .com "));

3. get matching results

Exec (str) performs search Matching. the returned value is the matching result (*), which is equivalent to match () and matches () in c ()

If exec () finds the matched text, an array of results is returned (a fully matched string and the results of the extraction group .). Otherwise, null is returned. To extract multiple data, you must call the exec () method repeatedly, which is similar to the matches () method.

Note the global mode /..... /G

In non-global mode, an exec () call is equivalent to match ();

Multiple consecutive calls in global mode are equivalent to matches ()

--- I case-insensitive

--- M multi-row matching

The above content is an introduction to the use of regular expressions in javascript. I hope you will like it.