JavaScript Replace function

Defined

The replace () function is used for replacing strings.

Grammar

Stringobject.replace (Regexp/substr, newsubstr/function)

Parameters

REGEXP/SUBSTR Regular Expression/string

Newsubstr/function Replace text/Generate alternate text function

Example

var str = "Visit microsoft!"; var res = str.replace ("Microsoft", "W3Schools");

Replace character

What does it mean if the replacement string Newsubstr contains the $ character?

A text that matches the 1th to 99th sub-expression in the $, $, ..., $ $ and regexp

$& and regexp matching substring

$ ' text on the left side of the matching substring

$ ' text on the right side of the matching substring

$$ Direct volume symbol.

What is the meaning of the sub-expression mentioned in the above $, $ ... An expression enclosed in parentheses in a regular expression.

/a/No sub-expression

/[a]/No sub-expression

/(a)/have sub-expression (a)

/(a), (b)/have sub-expressions (a), (b)

Example

Name = "Doe, John"; Name.replace (/(\w+) \s*, \s* (\w+)/, "$ $");//output "John Doe"

Replace function

Replace function description

function (Match, p1, P2,..., offset, string)

Match matches to the string

P1, p2 ... Sub-expression to match

Offset matches the position of the string

String Entire string

Example

var name = "Ace:mm-abc". Replace (/([\:\-\_]+ (.))        /, function (Match, p1, P2, offset, total) {Console.log ("match:" + _);        Console.log ("P1:" + separator);        Console.log ("P2:" + letter);        Console.log ("offset:" + offset); Console.log ("total:" + All) return offset? P2.touppercase (): p2;}) Console.log (name)/* Output substr::m TEST.HTML:43P1::MP2:MOFFSET:3TOTAL:ACE:MM-ABCACEMM-ABC */

There are two sub-expressions in the above regular expression

P1 is a sub-expression ([\:\-\_]+ (.)) Match to the content ": M"

P2 is a child form (.) Match to the content "M"