If specified, restricts dragging from starting unless the mousedown occurs on the specified element. Only elements that descend from the draggable element are permitted.
Examples
sample
<style>
.element { border: 1px solid #999; width: 300px; height: 200px; }
.handle { background-color: #DDD; cursor: move; width: 200px; margin: 5px auto 0px auto; text-align: center; padding: 5px; }
</style>
<div id="element" class="element">
<div id="handle" class="handle">Handle for dragging</div>
</div>
<script>
$('#element').draggable({
handle: $('#handle')
});
</script>