function getFocusElements(elm) {
			var elements = [];

			function collect(elm) {
				if (elm.nodeType != 1 || elm.style.display == 'none') {
					return;
				}

				if (canFocus(elm)) {
					elements.push(elm);
				}

				for (var i = 0; i < elm.childNodes.length; i++) {
					collect(elm.childNodes[i]);
				}
			}

			collect(elm || root.getEl());

			return elements;
		}
Returns an array of focusable visible elements within the specified container element.

@private
@param {Element} elm DOM element to find focusable elements within.
@return {Array} Array of focusable elements.