Dragging not working in Firefox and IE

Dragging not working in Firefox and IE

<a href="#"><img draggable src="http://placekitten.com/g/200/300"></a>
JS:
document.getElementsByTagName('img')[0].ondragstart = function(e){
console.log('dragging ' + this.nodeName);
};
http://jsfiddle.net/NT9FY/
It's also working in Opera.
Anyone know why this is happening? According to
http://caniuse.com/dragndrop all browsers should support drag and drop