05 改(replaceChild)

replaceChild 替换节点

    <div id="app">
 <p id="child">hello world</p>
    </div>
<!-- 替换节点
parentNode.replaceChild(newNode,targetNode); -->
<script>
 var app=document.getElementById("app");
 var h1=document.createElement("h1");
 h1.innerHTML="change";
 var child=document.getElementById("child");
 app.replaceChild(h1,child);