获取所有的元素节点
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
</head>
<body>
<ul id="app">
<li>hello world</li>
<li>hello world</li>
<li>hello world</li>
<li>hello world</li>
</ul>
<script>
// 获取所有的元素节点 下课自己写一遍
var app = document.getElementById("app");
var childs = app.childNodes;
var arr = [];
for(var i=0;i<childs.length;i++){
if(childs[i].nodeType == 1){
arr.push(childs[i])
}
}
console.log(arr);
</script>
</body>
</html>