/**
     * @author Alexander Farkas
     * v. 1.21
     */


    (function($) {
            if(!document.defaultView || !document.defaultView.getComputedStyle){ // IE6-IE8
                    var oldCurCSS = jQuery.curCSS;
                    jQuery.curCSS = function(elem, name, force){
                            if(name === 'background-position'){
                                    name = 'backgroundPosition';
                            }
                            if(name !== 'backgroundPosition' || !elem.currentStyle || elem.currentStyle[ name ]){
                                    return oldCurCSS.apply(this, arguments);
                            }
                            var style = elem.style;
                            if ( !force && style && style[ name ] ){
                                    return style[ name ];
                            }
                            return oldCurCSS(elem, 'backgroundPositionX', force) +' '+ oldCurCSS(elem, 'backgroundPositionY', force);
                    };
            }

            var oldAnim = $.fn.animate;
            $.fn.animate = function(prop){
                    if('background-position' in prop){
                            prop.backgroundPosition = prop['background-position'];
                            delete prop['background-position'];
                    }
                    if('backgroundPosition' in prop){
                            prop.backgroundPosition = '('+ prop.backgroundPosition;
                    }
                    return oldAnim.apply(this, arguments);
            };

            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]];
            }

            $.fx.step. backgroundPosition = function(fx) {
                    if (!fx.bgPosReady) {
                            var start = $.curCSS(fx.elem,'backgroundPosition');

                            if(!start){//FF2 no inline-style fallback
                                    start = '0px 0px';
                            }

                            start = toArray(start);

                            fx.start = [start[0],start[2]];

                            var end = toArray(fx.options.curAnim.backgroundPosition);
                            fx.end = [end[0],end[2]];

                            fx.unit = [end[1],end[3]];
                            fx.bgPosReady = true;
                    }
                    //return;
                    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];

            };
    })(jQuery);