返回一个引用来源 - 在线编辑器

          <p>这边引用了 WWF's 站点的内容:</p>
<blockquote id="myBlockquote" cite="http://www.worldwildlife.org/who/index.html">
  For 50 years, WWF has been protecting the future of nature. The world's leading conservation organization, WWF works in 100 countries and is supported by 1.2 million members in the United States and close to 5 million globally.
</blockquote>
<p>点击下面的按钮，返回以上引用cite属性的值。</p>
<p id="demo"></p>
<button onclick="myFunction()">点我</button>
<script>
  function myFunction() {
    var x = document.getElementById("myBlockquote").cite;
    document.getElementById("demo").innerHTML = x;
  }
</script>
        