/**
 * @author Alexander Farkas
 * v. 1.02
 */
(function($) {
 $.extend($.fx.step,{
 backgroundPosition: function(fx) {
 if (fx.state === 0 && typeof fx.end == 'string') {
 var start = $.curCSS(fx.elem,'backgroundPosition');
 start = toArray(start);
 fx.start = [start[0],start[2]];
 var end = toArray(fx.end);
 fx.end = [end[0],end[2]];
 fx.unit = [end[1],end[3]];
 }
 var nowPosX = [];
 nowPosX[0] = ((fx.end[0] - fx.start[0]) * fx.pos) + fx.start[0] + fx.unit[0];
 nowPosX[1] = ((fx.end[1] - fx.start[1]) * fx.pos) + fx.start[1] + fx.unit[1];
 fx.elem.style.backgroundPosition = nowPosX[0]+' '+nowPosX[1];

 function toArray(strg){
 strg = strg.replace(/left|top/g,'0px');
 strg = strg.replace(/right|bottom/g,'100%');
 strg = strg.replace(/([0-9\.]+)(\s|\)|$)/g,"$1px$2");
 var res = strg.match(/(-?[0-9\.]+)(px|\%|em|pt)\s(-?[0-9\.]+)(px|\%|em|pt)/);
 return [parseFloat(res[1],10),res[2],parseFloat(res[3],10),res[4]];
 }
 }
 });
})(jQuery);