<!DOCTYPE html>
<html lang="en-US">
<body>
<div id="point">
<p>Click <span>any</span></p>
<b>Button</b>
</div>
<button onclick="myParent()">Parent Node</button>
<button onclick="myAllChild()">All Child Node</button>
<button onclick="myFirstChild()">First Child</button>
<script>
var x = document.getElementById("point")
var walker = document.createTreeWalker(x, NodeFilter.SHOW_ELEMENT, null, false)
function myParent(){
walker.currentNode = x;
alert(walker.currentNode.tagName);
}
function myAllChild(){
walker.currentNode = x;
while(walker.nextNode())
alert(walker.currentNode.tagName)
}
function myFirstChild(){
walker.currentNode = x;
alert(walker.firstChild().tagName);
}
</script> </body>
</html>