Guidelines for using regular expressions in JavaScript _javascript tips

How to use

1. Create an expression

Methods for creating regular expression classes in javascript:

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

/Expression/is the syntax provided in JavaScript specifically to simplify regular expression writing, and regular expressions written in//are not used for escape characters.

Ways to RegExp objects:

2. Judge whether the match

Test (str) determines whether string str matches a regular expression, equivalent to IsMatch

Copy Code code as follows:

var regex = /.+@.+/;
Alert (Regex.test ("a@b.com"));
Alert (Regex.test ("ab.com"));

3. Get match result

Exec (str) for search match, return value is match result (*), equivalent to match () and matches ()

In C # if EXEC () If a matching text is found, it returns an array of results (the exact matching string and the result of the extraction group). ）。 Otherwise, NULL is returned. To extract multiple calls to Exec () is similar to the matches () method.

Note Global mode        /...../g

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

Repeated calls in global mode equivalent to matches ()

---I ignore case

---m multiline match

The above is the introduction of the use of the JavaScript's right expression, I hope you can enjoy it.