tyrostone/index.html

## index.html
<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width">
  <title>JS Bin</title>
</head>
<body>
  <!-- <button id="button">Click me</button> -->
  <div id="parent" style="width:200px; height:200px; background-color:red">
    <div id="widget" style="position:absolute; width:150px; background-color: blue; color: white;">
      Drag Me!
    </div>
  </div>
<script src="https://cdnjs.cloudflare.com/ajax/libs/rxjs/4.0.6/rx.all.js"></script>
<script src="simpleDragAndDrop.js"></script>
</body>
</html>

## simpleDragAndDrop.js
var parent = document.getElementById('parent');
var widget = document.getElementById('widget');

var mousedowns = observable.fromEvent(widget, "mousedown");
var parentMouseMoves = observable.fromEvent(parent, "mousemove");
var parentMouseUps = observable.fromEvent(parent, "mouseup");

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

var subscription = drags.forEach(
    function onNext(drag) {
      widget.style.left = drag.clientX + "px";
      widget.style.top = drag.clientY + "px";
  },
    function onError(error) {
  },
    function onCompleted() {
  });
	<!DOCTYPE html>
	<html>
	<head>
	<meta charset="utf-8">
	<meta name="viewport" content="width=device-width">
	<title>JS Bin</title>
	</head>
	<body>
	<!-- <button id="button">Click me</button> -->
	<div id="parent" style="width:200px; height:200px; background-color:red">
	<div id="widget" style="position:absolute; width:150px; background-color: blue; color: white;">
	Drag Me!
	</div>
	</div>
	<script src="https://cdnjs.cloudflare.com/ajax/libs/rxjs/4.0.6/rx.all.js"></script>
	<script src="simpleDragAndDrop.js"></script>
	</body>
	</html>
	var parent = document.getElementById('parent');
	var widget = document.getElementById('widget');

	var mousedowns = observable.fromEvent(widget, "mousedown");
	var parentMouseMoves = observable.fromEvent(parent, "mousemove");
	var parentMouseUps = observable.fromEvent(parent, "mouseup");

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

	var subscription = drags.forEach(
	function onNext(drag) {
	widget.style.left = drag.clientX + "px";
	widget.style.top = drag.clientY + "px";
	},
	function onError(error) {
	},
	function onCompleted() {
	});