具体步骤如下：
1、快捷键：Ctrl + R
2、输入：%windir%System32inetsrvconfigapplicationHost.config
3、注销：fileExtensions节下的：<!--<add fileExtension=".config" allowed="false" /> --> 和 hiddenSegments 节下的<!-- <add segment="web.config" /> -->。具体如下：
<requestFiltering>
<fileExtensions allowUnlisted="true" applyToWebDAV="true">
<add fileExtension=".asa" allowed="false" />
<add fileExtension=".asax" allowed="false" />
<add fileExtension=".ascx" allowed="false" />
<add fileExtension=".master" allowed="false" />
<add fileExtension=".skin" allowed="false" />
<add fileExtension=".browser" allowed="false" />
<add fileExtension=".sitemap" allowed="false" />
<!--<add fileExtension=".config" allowed="false" /> -->
<add fileExtension=".cs" allowed="false" />
<add fileExtension=".csproj" allowed="false" />
<add fileExtension=".vb" allowed="false" />
<add fileExtension=".vbproj" allowed="false" />
<add fileExtension=".webinfo" allowed="false" />
<add fileExtension=".licx" allowed="false" />
<add fileExtension=".resx" allowed="false" />
<add fileExtension=".resources" allowed="false" />
<add fileExtension=".mdb" allowed="false" />
<add fileExtension=".vjsproj" allowed="false" />
<add fileExtension=".java" allowed="false" />
<add fileExtension=".jsl" allowed="false" />
<add fileExtension=".ldb" allowed="false" />
<add fileExtension=".dsdgm" allowed="false" />
<add fileExtension=".ssdgm" allowed="false" />
<add fileExtension=".lsad" allowed="false" />
<add fileExtension=".ssmap" allowed="false" />
<add fileExtension=".cd" allowed="false" />
<add fileExtension=".dsprototype" allowed="false" />
<add fileExtension=".lsaprototype" allowed="false" />
<add fileExtension=".sdm" allowed="false" />
<add fileExtension=".sdmDocument" allowed="false" />
<add fileExtension=".mdf" allowed="false" />
<add fileExtension=".ldf" allowed="false" />
<add fileExtension=".ad" allowed="false" />
<add fileExtension=".dd" allowed="false" />
<add fileExtension=".ldd" allowed="false" />
<add fileExtension=".sd" allowed="false" />
<add fileExtension=".adprototype" allowed="false" />
<add fileExtension=".lddprototype" allowed="false" />
<add fileExtension=".exclude" allowed="false" />
<add fileExtension=".refresh" allowed="false" />
<add fileExtension=".compiled" allowed="false" />
<add fileExtension=".msgx" allowed="false" />
<add fileExtension=".vsdisco" allowed="false" />
<add fileExtension=".rules" allowed="false" />
</fileExtensions>
<verbs allowUnlisted="true" applyToWebDAV="true" />
<hiddenSegments applyToWebDAV="true">
<!-- <add segment="web.config" /> -->
<add segment="bin" />
<add segment="App_code" />
<add segment="App_GlobalResources" />
<add segment="App_LocalResources" />
<add segment="App_WebReferences" />
<add segment="App_Data" />
<add segment="App_Browsers" />
</hiddenSegments>
</requestFiltering>
4、点击网站XXX，在右侧的IIS栏里，双击MIME类型项，在新打开的对话框中右侧（右击）点击添加，类型如：.config MIME类型如：xml/txt
完毕后就可以浏览web.config了，浏览其他后缀步骤更简单。。。