Web/JavaScript/Reference/Global objects/RegExp/input

Non-standard This feature is non-standard and is not on a standards track. Do not use it on production sites facing the Web: it will not work for every user. There may also be large incompatibilities between implementations and the behavior may change in the future.

The non-standard input property is a static property of regular expressions that contains the string against which a regular expression is matched. RegExp.$_ is an alias for this property.

Description

The input property is static, it is not a property of an individual regular expression object. Instead, you always use it as RegExp.input or RegExp.$_.

The value of the input property is modified whenever the searched string on the regular expression is changed and that string is matching.

Examples

Using input and $_

var re = /hi/g;
re.test('hi there!');
RegExp.input;         // "hi there!"
re.test('foo');       // new test, non-matching
RegExp.$_;            // "hi there!"
re.test('hi world!'); // new test, matching
RegExp.$_;            // "hi world!"

Specifications

Specification
Legacy RegExp features in JavaScript

Browser compatibility

The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.

Update compatibility data on GitHub

	Desktop						Mobile						Server
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet	Node.js
RegExp.input ($_) Non-standard'	Chrome Full support 1	Edge Full support 12	Firefox Full support 1	IE Full support 5.5	Opera Full support 15	Safari Full support 3	WebView Android Full support 1	Chrome Android Full support 18	Firefox Android Full support 4	Opera Android Full support 14	Safari iOS Full support 1	Samsung Internet Android Full support 1.0	nodejs Full support Yes

Legend

Full support  

Full support

Non-standard. Expect poor cross-browser support.'

Non-standard. Expect poor cross-browser support.

See also

• RegExp.lastMatch ($&)
• RegExp.lastParen ($+)
• RegExp.leftContext ($`)
• RegExp.rightContext ($')
• RegExp.$1-$9

RegExp.input ($_) by Mozilla Contributors is licensed under CC-BY-SA 2.5.