簡單的遍歷，熟悉一下dom節點的屬性，用的是html Dom ,節點還可以用xml 的dom來解析比如把children 換成childNodes,文本節點便會被統計進來，順便實現了簡單的map功能
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title></title>
</head>
<body>
<div class="section">
<input id="search"/>
<input id="search"/>
<input id="search"/>
<input id="search"/>
<ul id="datalist">
<li></li>
<li></li>
<li></li>
<li></li>
</ul>
</div>
</body>
<script type="text/javascript">
var map = {};
function printTree(node){
// console.log(node.nodeName.toLowerCase(),node.nodeType);
var temp_tag = node.nodeName.toLowerCase();
if(map[temp_tag]!=null)map[temp_tag]++;
else map[temp_tag]=1;
if(node.children!=null){
for (var i = 0; i < node.children.length; i++) {
printTree(node.children[i]);
}
}else {return;};
}
window.onload = function(){
printTree(document.body);
for (o in map) {
console.log(o+':'+map[o]);
}
}
</script>
</html>