[haXe] Another haxeJs newbie question

[Axel Huizinga]

Hi,
first I wonder why

        var a:HtmlCollection<StyleSheet> = js.Lib.document.stylesheets;
        trace(a);

reports null though I have one external stylesheet linked to my html 
document.

And then I'd like to change stylesheet rules via javascript.
Is there a way to do this with haxe?

Cordially,
Axel