<!DOCTYPE html>
<html>
<head>
<title>代码演示</title>
<meta charset="utf-8">
</head>
<body>
<!--简单的代码演示效果器 -->
<textarea id="J_textarea"></textarea>
<button id="submitVale">提交</button>
<div id="J_iframewapper"></div>
<script type="text/javascript">
var Jbtn = document.getElementById(‘submitVale‘);
var ifwapper = document.getElementById(‘J_iframewapper‘);
var otextAr = document.getElementById(‘J_textarea‘);
Jbtn.addEventListener(‘click‘, function() {
var text = otextAr.value;
var _iframe = document.createElement("iframe");
_iframe.setAttribute(‘id‘, ‘iframer‘);
ifwapper.innerHTML = ‘‘;
ifwapper.appendChild(_iframe);
var ifrw = (_iframe.contentWindow) ? _iframe.contentWindow : (_iframe.contentDocument.document) ? _iframe.contentDocument.document : _iframe.contentDocument;
ifrw.document.open();
ifrw.document.write(text);
ifrw.document.close();
}, false);
</script>
</body>
</html>
原文：http://www.cnblogs.com/superZz/p/5854696.html