第一步：打开文件夹 C:\WINDOWS\Microsoft.NET\Framework\v4.0.30319\Config\Browsers。
第二步：在Browsers文件夹中，找到文件 ie.browser 并打开。
第三步：将以下代码添加进去，保存。
<!-- Mozilla/5.0 (Windows NT 6.3; Trident/7.0; rv:11.0) like Gecko -->
<browser id="IE11Preview" parentID="Mozilla">
<identification>
<userAgent match="Trident/(?‘layoutVersion‘\d+).*rv:(?‘revision‘(?‘major‘\d+)(\.(?‘minor‘\d+)?))" />
<userAgent nonMatch="MSIE" />
</identification>
<capabilities>
<capability name="browser" value="IE" />
<capability name="layoutEngine" value="Trident" />
<capability name="layoutEngineVersion" value="${layoutVersion}" />
<capability name="isColor" value="true" />
<capability name="screenBitDepth" value="8" />
<capability name="ecmascriptversion" value="3.0" />
<capability name="jscriptversion" value="6.0" />
<capability name="javascript" value="true" />
<capability name="javascriptversion" value="1.5" />
<capability name="w3cdomversion" value="1.0" />
<capability name="ExchangeOmaSupported" value="true" />
<capability name="activexcontrols" value="true" />
<capability name="backgroundsounds" value="true" />
<capability name="cookies" value="true" />
<capability name="frames" value="true" />
<capability name="javaapplets" value="true" />
<capability name="supportsCallback" value="true" />
<capability name="supportsFileUpload" value="true" />
<capability name="supportsMultilineTextBoxDisplay" value="true" />
<capability name="supportsMaintainScrollPositionOnPostback" value="true" />
<capability name="supportsVCard" value="true" />
<capability name="supportsXmlHttp" value="true" />
<capability name="tables" value="true" />
<capability name="supportsAccessKeyAttribute" value="true" />
<capability name="tagwriter" value="System.Web.UI.HtmlTextWriter" />
<capability name="vbscript" value="true" />
<capability name="revmajor" value="${major}" />
<capability name="revminor" value="${minor}" />
</capabilities>
</browser>
第四步：在开始-->运行中执行 c:\WINDOWS\Microsoft.NET\Framework\v4.0.30319\aspnet_regbrowsers.exe -i
第五步：重起IIS服务。
至此，全部OK啦。
Windows Server 2003下ASP.NET无法识别IE11的解决方法
原文：http://www.cnblogs.com/kxjhfeilong/p/4493734.html