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JavaScript RegExp ?= Quantifier

RegExp Object Reference JavaSript RegExp Object

Definition and Usage

The ?=n quantifier matches any string that is followed by a specific string n.

Syntax

new RegExp("regexp(?=n)")

or

/regexp(?=n)/

Example

Example

Do a global search for "is" followed by " all":

var str="Is this all there is";
var patt1=/is(?= all)/g;

The marked text below shows where the expression gets a match:

Is this all there is

Try it yourself »

RegExp Object Reference JavaSript RegExp Object

From http://www.w3schools.com (Copyright Refsnes Data)