/*
 Drag & Drop
*/

var parent= document.getElementById('parent');
var widget= document.getElementById('widget');

var mouseDowns= Observable.fromEvent(widget, 'mousedown');
var parentMouseMoves= Observable.fromEvent(parent, 'mousemove');
var parentMouseUp= Observable.fromEvent(parent, 'mosueup');

var drags=
  mouseDowns.
    map(function(e) {
      return parentMouseMoves.
        takeUntil(parentMouseUps);
    }).
    concatAll();

drags.forEach(function(e) {
  widget.style.left= e.clientX + 'px';
  widget.style.top= e.clientY + 'px';
});