ol reverse attribute polyfill

html5Ol.js

//use this if you want support for browsers which don't have ES5 goodies
if (!('reversed' in document.createElement('ol'))) {
	(function () {

		var lists = document.getElementsByTagName('ol'),
			i = 0,
			len = lists.length,

			reverseList = function (list) {

				var children = [],
					childNodes = list.childNodes,
					count = list.getAttribute('start'),
					i,
					len,
					val;

				for (i = 0, len = childNodes.length; i < len; i++) {
					// Node.ELEMENT_NODE === 1
					if (childNodes[i].nodeType === 1) {
						children.push(childNodes[i]);
					}
				}

				//check to see if a start attribute is provided
				if (count !== null) {
					count = Number(count);
					if (isNaN(count)) {
						count = null;
					}
				}

				//no, this isn't duplication - start will be set to null
				// in the previous if statement if an invalid start attribute
				// is provided
				if (count === null) {
					count = children.length;
				}

				for (i = 0, len = children.length; i < len; i++) {
					val = children[i].getAttribute('value');
					if (val !== null && !isNaN(Number(val))) {
						count = val;
					}
					children[i].value = count--;
				}
			};

		for (i; i < len; i++) {
			if (lists[i].getAttribute('reversed') !== null) {
				reverseList(lists[i]);
			}
		}

	}());
}

html5OlEs5.js

//a polyfill for the ordered-list reversed attribute
// http://www.whatwg.org/specs/web-apps/current-work/multipage/grouping-content.html#the-ol-element
// http://www.whatwg.org/specs/web-apps/current-work/multipage/grouping-content.html#dom-li-value

//uses these awesomeness:
// Array.prototype.forEach
// Element.prototype.children
//if you want support for older browsers *cough*IE8-*cough*, then use the other
// file provided
(function () {
	'use strict';

	if ('reversed' in document.createElement('ol')) {
		return;
	}

	function reverseList(list) {

		var children = list.children,
			count = list.getAttribute('start'),
			val;

		// Check to see if a start attribute is provided
		if (count !== null) {
			count = Number(count);
			if (isNaN(count)) {
				count = null;
			}
		}

		//no, this isn't duplication - start will be set to null
		// in the previous if statement if an invalid start attribute
		// is provided
		if (count === null) {
			count = children.length;
		}

		[].forEach.call(children, function (child) {
			val = child.getAttribute('value');
			if (val !== null && !isNaN(Number(val))) {
				count = val;
			}
			child.value = count--;
		});

	}

	[].forEach.call(document.getElementsByTagName('ol'), function (list) {
		if (list.getAttribute('reversed') !== null) {
			reverseList(list);
		}
	});

}());