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:
string.replace(regexp/substr, newSubStr/function[, flags]); |
Here is the detail of parameters:
- 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:
Following example shows how to use the global and ignore case flags which permits replace to replace each occurrence of 'apples' in the string with 'oranges'.
<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> |
To understand it in better way you can Try it yourself.
Example:
Following example shows how to switch words in a string:
<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> |
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