代码在下面:
<div class="parent">
<div class="child">
<p>学习Java</p>
</div>
</div>
<script type="text/javascript">
var newElement = document.createElement("h1");
newElement.textContent = "学习JavaScript";
var oldElement = document.querySelector("p");
oldElement.parentNode.replaceChild(newElement,oldElement);
console.log(newElement); //Chrome输出: <h1>学习JavaScript</h1>
console.log(oldElement); //Chrome输出: <p>学习Java</p>
console.log(oldElement.parentNode.replaceChild(newElement,oldElement)); //Uncaught TypeError: Cannot read property 'replaceChild' of null
</script>