(function(a){a.extend(a.fx.step,{backgroundPosition:function(b){if(b.state===0&&typeof b.end=="string"){var d=a.curCSS(b.elem,"backgroundPosition");d=f(d);b.start=[d[0],d[2]];var e=f(b.end);b.end=[e[0],e[2]];b.unit=[e[1],e[3]]}var c=[];c[0]=(b.end[0]-b.start[0])*b.pos+b.start[0]+b.unit[0];c[1]=(b.end[1]-b.start[1])*b.pos+b.start[1]+b.unit[1];b.elem.style.backgroundPosition=c[0]+" "+c[1];function f(a){a=a.replace(/left|top/g,"0px");a=a.replace(/right|bottom/g,"100%");a=a.replace(/([0-9\.]+)(\s|\)|$)/g,"$1px$2");var b=a.match(/(-?[0-9\.]+)(px|\%|em|pt)\s(-?[0-9\.]+)(px|\%|em|pt)/);return[parseFloat(b[1],10),b[2],parseFloat(b[3],10),b[4]]}}})})(jQuery)