code: function _index(/**HTMLElement*/el) {
  		var index = 0;
  		while (el && (el = el.previousElementSibling)) {
  			if (el.nodeName.toUpperCase() !== 'TEMPLATE') {
  				index++;
  			}
  		}
  		return index;
  	}
docs: Returns the index of an element within its parent
  @param el
  @returns {number}
  @private