JavaScript RegExp \B Metacharacter


Example

Find the first occurrence of "LO", NOT at the beginning of a word:

let text = "HELLO, LOOK AT YOU!";
let pattern = /\BLO/;
Try it Yourself »

Description

The \B metacharacter matches NOT at the beginning/end of a word.

Search for the pattern LO, not at the beginning of a word like this:
\BLO

Search for the pattern LO, not at the end of a word like this:
LO\B

Browser Support

/\B/ is an ECMAScript1 (ES1) feature.

ES1 (JavaScript 1997) is fully supported in all browsers:

Chrome Edge Firefox Safari Opera IE
Yes Yes Yes Yes Yes Yes


Syntax

new RegExp("\\Bregexp")

or simply:

/\Bregexp/

Syntax with modifiers

new RegExp("\\Bregexp", "g")

or simply:

/\Bregexp/g

More Examples

Example

Find the first occurrence of "LO", NOT at the END of a word:

let text = "HELLO, LOOK AT YOU";
let pattern = /LO\B/;
Try it Yourself »

Regular Expression Search Methods

In JavaScript, a regular expression text search, can be done with different methods.

With a pattern as a regular expression, these are the most common methods:

ExampleDescription
text.match(pattern)The String method match()
text.search(pattern)The String method search()
pattern.exec(text)The RexExp method exec()
pattern.test(text)The RegExp method test()

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