1
  2// Node.prototype.contains
  3(function() {
  4
  5	function contains(node) {
  6		if (!(0 in arguments)) {
  7			throw new TypeError('1 argument is required');
  8		}
  9
 10		do {
 11			if (this === node) {
 12				return true;
 13			}
 14		// eslint-disable-next-line no-cond-assign
 15		} while (node = node && node.parentNode);
 16
 17		return false;
 18	}
 19
 20	// IE
 21	if ('HTMLElement' in self && 'contains' in HTMLElement.prototype) {
 22		try {
 23			delete HTMLElement.prototype.contains;
 24		// eslint-disable-next-line no-empty
 25		} catch (e) {}
 26	}
 27
 28	if ('Node' in self) {
 29		Node.prototype.contains = contains;
 30	} else {
 31		document.contains = Element.prototype.contains = contains;
 32	}
 33
 34}());
 35