运行代码框

<script>function runCode() {  var code=event.srcElement.parentElement.children[0].value; var newwin=window.open('','','');    newwin.opener = null; newwin.document.write(code);    newwin.document.close();  }</script>
<p><span><textarea rows="12" cols="70">这里插入运行代码</textarea><br />
<input type="button" onclick='runCode()' value="运行代码" /></span></p>