I have the following code, and I don't understand what is wrong, what is that IE8 don't like about it

```
var flap = $("#flap");
var animationSupport = _g.animationDetection();

if(animationSupport) {
    flap.addClass("showAnimation");
}
else {
    flap.css('width', flap.width() + 'px').css('right', '-' + flap.width() + 'px');
    flap.animate({right: 0}, 1500);
}

```

When I do this, I have the message: 

```
Object doesn't support property or method 'width'

```

Though , if I do the following, seems to be fine:

```
$("#flap").css("width", "300px").css("right", "-300px");

```