code: function(elem, attr) {
  		// for each attributeName
  		for (var name in attr) {
  			if (attr.hasOwnProperty(name)) {
  				// attributes
  				elem.setAttribute(name, attr[name]);
  			}
  		}
  		return elem;
  	}
docs: Appends an attribute to an element
  
  @private
  @param {Node} elem The element
  @param {Object} attr Attributes object
  @return {Node}