<h3>演示如何访问 BLOCKQUOTE 元素</h3>
<p>Here is a quote from WWF's website:</p>
<blockquote id="myBlockquote" cite="http://www.worldwildlife.org/who/index.html">
For 50 years, WWF has been protecting the future of nature.
<button onclick="myFunction()">试一下</button>
var x = document.getElementById("myBlockquote").cite;
document.getElementById("demo").innerHTML = x;