通过浏览器实例展示了如何在修改iframe中文档的背景颜色 - 在线编辑器

          <!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <title>蜜蜂教程(mifengjc.com)</title>
  <script>
    function changeStyle() {
      var x = document.getElementById("myframe");
      var y = (x.contentWindow || x.contentDocument);
      if (y.document) y = y.document;
      y.body.style.backgroundColor = "#0000ff";
    }
  </script>
</head>
<body>

  <iframe id="myframe" src="/examples/demo_iframe.htm">
<p>你的浏览器不支持iframes。</p>
</iframe>
  <br><br>
  <input type="button" onclick="changeStyle()" value="修改背景颜色">

</body>
</html>
        