Navigating Away from a Page that has Changes, in ASP.NET

链接地址：http://www.codeproject.com/KB/aspnet/NavAwayFromPage.aspx

Introduction

This code enables a Web page to notify users that they are leaving a page that they have made modifications to. Why is this useful? Well, the previous sentence says it all. We want to notify the user that they have made modifications to a page and ask them if they really want to leave the page. It is assumed that you are familiar with JavaScript, DOM Events, and ASP.NET 1.x or higher. The included project is in Visual Studio 2005.