JavaScript String - replace() Method
Description
This method finds a match between a regular expression and a string, and replaces the matched substring with a new substring.
The replacement string can include the following special replacement patterns −
Pattern | Inserts |
---|---|
$$ | Inserts a "$". |
$& | Inserts the matched substring. |
$` | Inserts the portion of the string that precedes the matched substring. |
$' | Inserts the portion of the string that follows the matched substring. |
$n or $nn | Where n or nn are decimal digits, inserts the nth parenthesized submatch string, provided the first argument was a RegExp object. |
Syntax
The syntax to use the replace() method is as follows −
string.replace(regexp/substr, newSubStr/function[, flags]);
Argument Details
regexp − A RegExp object. The match is replaced by the return value of parameter #2.
substr − A String that is to be replaced by newSubStr.
newSubStr − The String that replaces the substring received from parameter #1.
function − A function to be invoked to create the new substring.
flags − A String containing any combination of the RegExp flags: g - global match, i - ignore case, m - match over multiple lines. This parameter is only used if the first parameter is a string.
Return Value
It simply returns a new changed string.
Example
Try the following example.
Live Demo<html> <head> <title>JavaScript String replace() Method</title> </head> <body> <script type = "text/javascript"> var re = /apples/gi; var str = "Apples are round, and apples are juicy."; var newstr = str.replace(re, "oranges"); document.write(newstr ); </script> </body> </html>
Output
oranges are round, and oranges are juicy.
Example
Try the following example; it shows how to switch words in a string.
Live Demo<html> <head> <title>JavaScript String replace() Method</title> </head> <body> <script type = "text/javascript"> var re = /(\w+)\s(\w+)/; var str = "zara ali"; var newstr = str.replace(re, "$2, $1"); document.write(newstr); </script> </body> </html>
Output
ali, zara