FireFox cannot get mouse position on drag

Question

I have the following code in Angular

element.bind('dragstart', function(){ // set the drag start parameter});
element.bind('dragend', function(){ // set the drag end parameter});
element.bind('drag, function(event){
    console.log(event.originalEvent.pageY);
});

However, this just returns the same number no matter what. If I stop dragging, and restart dragging, then it returns the pageY when the drag started and stays on that number! Why?