1 <html xmlns="[url]http://www.w3.org/1999/xhtml[/url]"> 2 <head> 3 <meta http-equiv="Content-Type" content="text/html; charset=gb2312" /> 4 <title>onbeforeunload测试</title> 5 <script> 6 function checkLeave(){ 7 event.returnValue=""; 8 } 9 </script> 10 </head> 11 <body onbeforeunload="checkLeave()"> 12 </body> 13 </html>