开启网站维护状态

有时候网站需要进入维护状态，访客访问的时候给他一个提示信息即可，有没有什么简单易操作的方式呢？

这里介绍一个解决办法，直接在根目录放置一个“App_Offline.htm”文件即可，文件名不能修改，文件内容可以是一个维护状态说明：

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml">
<head>
    <title>Down for Maintenance</title>
        <style type="text/css">
        * {
            margin: 0;
            padding: 0;
        }

        a {
            text-decoration: underline;
            color: #FF381A;
        }

        a:hover {
            text-decoration: none;
        }

        body {
            line-height: 1.75em;
            background: #fff;
            font-size: 11.5pt;
            color: #5A6466;
        }

        body,input {
            font-family: Kreon, serif;
        }

        br.clearfix {
            clear: both;
        }

        h1,h2,h3,h4 {
            text-transform: uppercase;
            font-weight: normal;
        }

        h2 {
            font-size: 1.5em;
        }

        h2,h3,h4 {
            font-family: "Open Sans", sans-serif;
            color: #2A3436;
            margin-bottom: 1em;
        }

        h3 {
            font-size: 1.25em;
        }

        h4 {
            font-size: 1em;
        }

        img.alignleft {
            float: left;
            margin: 5px 30px 20px 0;
        }

        img.aligntop {
            margin: 5px 0 20px 0;
        }

        p {
            margin-bottom: 1.5em;
        }

        a {
            color: #2A3436;
        }

        .box {
            margin: 0 0 250px 0;
        }

        img.alignleft {
            float: left;
            margin: 5px 30px 30px 0;
            border-radius: 6px;
        }

        img.aligntop {
            margin: 5px 0 20px 0;
            border-radius: 6px;
        }

        #content {
            padding: 0;
            width: 815px;
            margin: 0 0 0 0px;
        }


        #page {
            margin: 0;
            position: relative;
            width: 900px;
            padding: 20px 40px 0 40px;
        }


        #wrapper {
            width: 978px;
            position: relative;
            background: #FFF;
            margin: 0 auto 0 auto;
            box-shadow: 0px 0px 300px 0px rgba(0,0,0,0.15);
            border: solid 1px #82A7AD;
            
        }

        
    </style>

</head>
<body>
    <div>&nbsp;</div>
    <div id="wrapper">
        
        <div id="page">
            <div id="content">

                <div class="box">
                    <h2>Website is Down for maintenance</h2>
                    <img class="alignleft" src="/Images/logo.jpg" alt="Down for maintenance" title="Down for maintenance" />
                    <p>
                        We&#39;re currently undergoing scheduled maintenance. We will come back very shortly. Please check back in fifteen minutes. Thank you for your patience.
                    </p>
                </div>
            </div>
        </div>
    </div>

</body>
</html>