JS: Regex Find/Replace

By Xah Lee. Date: . Last updated: .

Regex means Regular Expression. It is used to check if a string contains certain pattern, or extract the pattern, or replace it with other string. For example, extract email addresses in a text file.

For basic tutorial, see JS: RegExp Tutorial

There are 2 ways to use RegExp in JavaScript:

Following is a summary of the different methods.



Get the index of first char of matched string.

[see JS: String.prototype.search]


Get a array of captured groups, or, get array of all occurrences.

[see JS: String.prototype.match]



Get a new string.

[see JS: String.prototype.replace]



Return true or false.

[JS: RegExp.prototype.test]



Return a array of captured groups.

[JS: RegExp.prototype.exec]

RegExp Topic

  1. JS: RegExp Tutorial
  2. JS: RegExp Syntax
  3. JS: Regex Find/Replace
  4. JS: RegExp Object
  5. JS: RegExp Constructor
  6. JS: RegExp.prototype

String Topic

  1. JS: Source Code Encoding
  2. JS: String Code Unit vs Code Point
  3. JS: Unicode Character Escape Sequence
  4. JS: Allowed Characters in Identifier
  5. HTML: Allowed Characters in id Attribute
  6. HTML: Character Sets and Encoding
  7. HTML/XML Entity List

  1. JS: Template String
  2. JS: Convert String to Number
  3. JS: Encode URL, Escape String
  4. JS: Format Number
  5. JS: JSON

  1. JS: String Object
  2. JS: String.prototype
  3. JS: String Constructor
Liket it? Put $5 at patreon.

Or, Buy JavaScript in Depth

Ask me question on patreon