/**
* @author Alexander Farkas
* Allows background position to be changed in JQUERY
* v. 1.02
*/
(function($) {
  $.extend($.fx.step,{
    backgroundPosition: function(fx) {
      if (fx.state === 0 && typeof fx.end == 'string') {
       	var start = $.curCSS(fx.elem,'backgroundPosition');
				if(typeof(start) === 'undefined') {
					start = $.curCSS(fx.elem,'backgroundPositionX') + ' ' + $.curCSS(fx.elem,'backgroundPositionY');
				}
        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);