<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Drag Handle</title>
<style>
#draggable {
width: 100px;
height: 100px;
border: 1px solid black;
}
#handle {
width: 0;
height: 0;
border-right: 20px solid transparent;
border-top: 20px solid black;
cursor: move;
}
</style>
</head>
<body>
<h1>Drag Handle</h1>
<div id="draggable" draggable="true">
<div id="handle">
</div>
</div>
<script>
var draggable = document.getElementById('draggable');
var handle = document.getElementById('handle');
var target = false;
draggable.onmousedown = function(e) {
target = e.target;
};
draggable.ondragstart = function(e) {
if (handle.contains(target)) {
e.dataTransfer.setData('text/plain', 'handle');
} else {
e.preventDefault();
}
};
</script>
</body>
</html>