DOM节点----------
创建新元素(DOM树中的新节点)
var p = document.createElement("p");
p.innerHTML="xxx";
ele.appendChild(p);//把新创建的节点添加到DOM树中
创建文本节点
var node=document.createTextNode("xxxxx");
ele.appendChild(node);
删除元素(删除节点)
ele.removeChild(node);
<!DOCTYPE html>
<head>
<meta charset="UTF-8">
<title>添加新节点</title>
</head>
<body>
<div id="mydiv">
<span>第一个span</span>
<span>第二个span</span>
<span>第三个span</span>
<span>第四个span</span>
<p id="myp">我是p标签</p>
</div>
</body>
</html>
<script type="text/javascript">
myp = document.getElementById("myp");
// myp.innerHTML = "<span>第五个span</span>";
mydiv = document.getElementById("mydiv");
mydiv.removeChild(myp);
// mydiv.innerHTML = "<span>第六个span</span>";
var newSpan = document.createElement("span"); //<span></span>
// newSpan.innerText = "我是第五个span";
var textNode = document.createTextNode("我是第五个 span");
newSpan.appendChild(textNode);
mydiv.appendChild(newSpan);
</script>