[Decode]

<style>
	.hot {
		border: 1px dashed gray;
		padding: 5px;
		height: 100px;
		width: 100px;
		cursor: pointer;
	}
</style>

<div class="hot" id="auth"></div>

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.0/jquery.min.js"></script>

<script>
	$(function() {
		var client;
		var shiftY;

		$('#auth').mousedown(function() {
			client = true;
			shiftY = event.clientY - ( $('#auth').offset().top - $(window).scrollTop() );
		});

		$('body').mouseup(function() {
			client = false;
		}).mousemove(function(event) {
			var clientCoords = event.clientY - shiftY;

			if (client == true) {
				$('#auth').css({
					marginTop: clientCoords
				});
			}
		});
	});
</script>