jquery - jquery backgroundpositionY animation not working in firefox

Question

So I have a background I want to animate on a scroll event, works fine in chrome and safari.

Apparently though, firefox doesn't support this properly (and neither does opera).

Is there some other property I can use to animate the background that'll work cross browser?

$(document).scroll(function() {    
    var scroll = $(window).scrollTop();

    if (scroll >= 200) {
        $(".col-3-iphoneback").animate( { backgroundPositionY:"-223px"}, { queue:false, duration:1000 });
    } 


     if (scroll <= 200) {
        $(".col-3-iphoneback").animate( { backgroundPositionY:"0px" }, { queue:false, duration:1000 } );
    } 


});