火狐不支持backgroundPosition的js插件_html/css_WEB-ITnose

用js backgroundPositionX,backgroundPositionY设置在firefox下无法识别，用backgroundPosition同样在火狐无法识别。要识别只能用js插件来实现的，代码如下：

/** * @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);