msMatchesSelector

msMatchesSelector is a legacy DOM API method on the Element interface that tests whether a given element would be selected by a specified CSS selector. It is the Microsoft-prefixed version of the standard Element.matches method and was used in older Microsoft browsers. The method returns a boolean: true if the element would be selected by the selector, false otherwise.

Usage involves calling the function on an element with a CSS selector string. For example, element.msMatchesSelector('.active') returns true if the element would be matched by the selector .active in the document. This is functionally equivalent to element.matches('.active') in modern browsers, and it is commonly used in event delegation and conditional logic to determine if an element belongs to a particular set of elements.

Compatibility and fallbacks: Historically, different browsers exposed vendor-prefixed variants such as msMatchesSelector (Microsoft), webkitMatchesSelector (WebKit-based browsers), or mozMatchesSelector (Firefox). Modern code typically relies on the standardized Element.matches and uses a cross-browser fallback, for example by selecting the first available implementation from matches, msMatchesSelector, webkitMatchesSelector, or mozMatchesSelector. This approach ensures compatibility across older environments while benefiting from the standard API when available.

See also: Element.matches.