操作方法
<html xmlns="http://www.w3.org/1999/xhtml" > <head runat="server"> <title>测试</title> <script language="javascript" type="text/javascript"> function getStyle() { if (window.top == window.self) { document.getElementById("top").style.display = 'block'; } else { document.getElementById("top").style.display = 'none'; } } </script> </head> <body onload="getStyle();"> <form id="form1" runat="server"> <div id="top"> 在框架中不显示，正常访问显示 </div> </form> </body> </html>