The multiline property indicates whether or not the "m" flag is used with the regular expression. multiline is a read-only property of an individual regular expression instance.

Property attributes of RegExp.prototype.multiline
Writable no
Enumerable no
Configurable yes


The value of multiline is a Boolean and is true if the "m" flag was used; otherwise, false. The "m" flag indicates that a multiline input string should be treated as multiple lines. For example, if "m" is used, "^" and "$" change from matching at only the start or end of the entire string to the start or end of any line within the string.

You cannot change this property directly.


Using multiline

var regex = new RegExp('foo', 'm');

console.log(regex.multiline); // true


ECMAScript Latest Draft (ECMA-262)
The definition of 'RegExp.prototype.multiline' in that specification.

Browser compatibility

Update compatibility data on GitHub
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung InternetNode.js
multilineChrome Full support 1Edge Full support 12Firefox Full support 1IE Full support 5.5Opera Full support 5Safari Full support 1WebView Android Full support 1Chrome Android Full support 18Firefox Android Full support 4Opera Android Full support 10.1Safari iOS Full support 1Samsung Internet Android Full support 1.0nodejs Full support Yes
Prototype accessor property (ES2015)Chrome Full support 48Edge Full support 12Firefox Full support 38IE Full support 5.5Opera Full support 35Safari Full support 1.3WebView Android Full support 48Chrome Android Full support 48Firefox Android Full support 38Opera Android Full support 35Safari iOS Full support 1Samsung Internet Android Full support 5.0nodejs Full support Yes


Full support  
Full support

Compatibility notes

  • Prior to Firefox 48, a non-standard, global RegExp.multiline property existed in addition to this RegExp.prototype.multiline property. It is removed in newer versions (see bug 1219757). Use the property described on this page or the m flag instead.

See also