jquery animate background-position firefox

Question

I got this background image slider thing working in chrome and safari, but it doesnt do anything in firefox. any help?

$(function(){
    var image= ".main-content";
    var button_left= "#button_left";
    var button_right= "#button_right";
    var animation= "easeOutQuint";
    var time= 800;
    var jump= 800;
    var action= 0;

    $(button_left).click(function(){
        right();
    });
    $(button_right).click(function(){
        left();
    });
    $(document).keydown(function(event){
        if(event.keyCode == '37'){
            right();
        }
    });
    $(document).keydown(function(event){
        if(event.keyCode == '39'){
            left();
        }
    });
    function left(){
        if(action == 0){
            action= 1;
            $(image).animate({backgroundPositionX: '-='+jump+'px'}, {duration: time, easing: animation});
            setTimeout(anim, time);
        }

    }
    function right(){
        if(action == 0){
            action= 1;
            $(image).animate({backgroundPositionX: '+='+jump+'px'}, {duration: time, easing: animation});
            setTimeout(anim, time);
        }
    }
    function anim(){
        action= 0;
    }
}); 

I also tried this but it also does nothing

$(image).animate({backgroundPosition: '500px 0px'}, 800);

Answer 1

The version above doesn't work with jQuery 1.6.1. This one does.

(function($) {
if(!document.defaultView || !document.defaultView.getComputedStyle){
    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(/center/g,'50%');
    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.end);
        fx.end = [end[0],end[2]];

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

    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);