+ var parsed,
+ r = jQuery.css( this.elem, this.prop );
+ // Empty strings, null, undefined and "auto" are converted to 0,
+ // complex values such as "rotate(1rad)" are returned as is,
+ // simple values such as "10px" are parsed to Float.
+ return isNaN( parsed = parseFloat( r ) ) ? !r || r === "auto" ? 0 : r : parsed;