1 (function() {

     2 

     3 	function contains(node) {

     4 		if (!(0 in arguments)) {

     5 			throw new TypeError('1 argument is required');

     6 		}

     7 

     8 		do {

     9 			if (this === node) {

    10 				return true;

    11 			}

    12 		} while (node = node && node.parentNode);

    13 

    14 		return false;

    15 	}

    16 

    17 	// IE

    18 	if ('HTMLElement' in this && 'contains' in HTMLElement.prototype) {

    19 		try {

    20 			delete HTMLElement.prototype.contains;

    21 		} catch (e) {}

    22 	}

    23 

    24 	if ('Node' in this) {

    25 		Node.prototype.contains = contains;

    26 	} else {

    27 		document.contains = Element.prototype.contains = contains;

    28 	}

    29 

    30 }());