function canFocus(elm) {
			if (isTextInputElement(elm) && !elm.hidden) {
				return true;
			}

			if (/^(button|menuitem|checkbox|tab|menuitemcheckbox|option|gridcell|slider)$/.test(getRole(elm))) {
				return true;
			}

			return false;
		}
Returns true/false if the specified element can be focused or not.

@private
@param {Element} elm DOM element to check if it can be focused or not.
@return {Boolean} True/false if the element can have focus.