有时候在编辑页面用户做修改后，可能会有刷新、关闭等误操作造成当前页面信息的丢失，何不先提醒一下用户呢？实例代码如下：
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<html><head> <title>Confirm Before Leave</title> <script language="javascript" type="text/javascript"><!-- var pb_strConfirmCloseMessage; var pb_blnCloseWindow = false; pb_strConfirmCloseMessage ="您真的要离开本页吗?"; function ConfirmClose() { window.event.returnValue = pb_strConfirmCloseMessage; pb_blnCloseWindow = true; } function ShowConfirmClose(blnValue) { if(blnValue) { document.body.onbeforeunload = ConfirmClose; } else { document.body.onbeforeunload = null; } } //--></script></head><body οnlοad="ShowConfirmClose(true);"><input type=button value="提示" οnclick="ShowConfirmClose(true);"><input type=button value="不提示" οnclick="ShowConfirmClose(false);"><input type=button value="测试刷新" οnclick="window.location.reload();"></body></html>