JavaScript RegExp ?= Quantifier
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 »
Definition and Usage
The ?=n quantifier matches any string that is followed by a specific string n.
Tip: Use the ?!n quantifier to match any string that is NOT followed by a specific string n.
Browser Support
The ?= quantifier is supported in all major browsers.
Syntax
new RegExp("regexp(?=n)")
or
/regexp(?=n)/
Syntax with modifiers
new RegExp("regexp(?=n)","g")
or simply:
/\regexp(?=n)/g
JavaScript RegExp Object
