分享程序员开发的那些事...
更新时间：2023-09-03 18:07:46
（1）您的< ; script> 标记应放在结束< / body> 标记之前。您的JavaScript正在尝试操作尚未加载到DOM中的HTML元素。
（2）您对HTML内容的分配看起来很混乱。
（3）Be与元素ID中的情况一致，即'DIV2'与'Div2'
（4）'document'对象的用户小写（credit：ThatOtherPerson）
(1) Your <script> tag should be placed before the closing </body> tag. Your JavaScript is trying to manipulate HTML elements that haven't been loaded into the DOM yet.
(2) Your assignment of HTML content looks jumbled.
(3) Be consistent with the case in your element ID, i.e. 'DIV2' vs 'Div2'
(4) User lower case for 'document' object (credit: ThatOtherPerson)
<body>
<div id="DIV1">
// Some content goes here.
</div>
<div id="DIV2">
</div>
<script type="text/javascript">
var MyDiv1 = document.getElementById('DIV1');
var MyDiv2 = document.getElementById('DIV2');
MyDiv2.innerHTML = MyDiv1.innerHTML;
</script>
</body>