1 // element-closest | CC0-1.0 | github.com/jonathantneal/closest

     2 

     3 (function (ElementProto) {

     4 	if (typeof ElementProto.matches !== 'function') {

     5 		ElementProto.matches = ElementProto.msMatchesSelector || ElementProto.mozMatchesSelector || ElementProto.webkitMatchesSelector || function matches(selector) {

     6 			var element = this;

     7 			var elements = (element.document || element.ownerDocument).querySelectorAll(selector);

     8 			var index = 0;

     9 

    10 			while (elements[index] && elements[index] !== element) {

    11 				++index;

    12 			}

    13 

    14 			return Boolean(elements[index]);

    15 		};

    16 	}

    17 

    18 	if (typeof ElementProto.closest !== 'function') {

    19 		ElementProto.closest = function closest(selector) {

    20 			var element = this;

    21 

    22 			while (element && element.nodeType === 1) {

    23 				if (element.matches(selector)) {

    24 					return element;

    25 				}

    26 

    27 				element = element.parentNode;

    28 			}

    29 

    30 			return null;

    31 		};

    32 	}

    33 })(window.Element.prototype);