asp.net 项目在 IE 11 下出现 “__doPostBack”未定义 的解决办法
最近项目在 IE 11 下<asp:LinkButton> 点击出现 “__doPostBack”未定义”，经过一番google,终于知道了原因：ASP.NET 可能无法辨识出一些浏览器的最新版本，还会经常把它们看做是低级的浏览器。（也就是： 不支持JavaScript。）
详见： http://blogs.msdn.com/b/scott_hanselman/archive/2011/10/28/asp-net-ie10-dopostback-javascript-ff5.aspx
本人按照该文所提供的解决办法始终未能得到解决，于是按提示尝试用单个站点的方式修复。
在项目根目录 App_Browsers 下新建 浏览器文件(.browser)，让其与IE11的 UserAgent 匹配，使 .net framework 认识这是一个已知的浏览器，可以正常地向客户端输出脚本。
在文件里输入以下内容，保存即可。
<browsers>
<browser id=
"IE11"
parentID=
"Mozilla"
>
<identification>
<userAgent match=
"Trident\/7.0; rv:(?'version'(?'major'\d+)(\.(?'minor'\d+)?)(?'letters'\w*))(?'extra'[^)]*)"
/>
<userAgent nonMatch=
"IEMobile"
/>
</identification>
<capture>
<userAgent match=
"Trident/(?'layoutVersion'\d+)"
/>
</capture>
<capabilities>
<capability name=
"browser"
value=
"IE"
/>
<capability name=
"layoutEngine"
value=
"Trident"
/>
<capability name=
"layoutEngineVersion"
value=
"${layoutVersion}"
/>
<capability name=
"extra"
value=
"${extra}"
/>
<capability name=
"isColor"
value=
"true"
/>
<capability name=
"letters"
value=
"${letters}"
/>
<capability name=
"majorversion"
value=
"${major}"
/>
<capability name=
"minorversion"
value=
"${minor}"
/>
<capability name=
"screenBitDepth"
value=
"8"
/>
<capability name=
"type"
value=
"IE${major}"
/>
<capability name=
"version"
value=
"${version}"
/>
</capabilities>
</browser>
<!-- Mozilla/5.0 (Windows NT 6.3; Trident/7.0; rv:11,0) like Gecko -->
<browser id=
"IE110"
parentID=
"IE11"
>
<identification>
<capability name=
"majorversion"
match=
"11"
/>
</identification>
<capabilities>
<capability name=
"ecmascriptversion"
value=
"3.0"
/>
<capability name=
"jscriptversion"
value=
"5.6"
/>
<capability name=
"javascript"
value=
"true"
/>
<capability name=
"javascriptversion"
value=
"1.5"
/>
<capability name=
"msdomversion"
value=
"${majorversion}.${minorversion}"
/>
<capability name=
"w3cdomversion"
value=
"1.0"
/>
<capability name=
"ExchangeOmaSupported"
value=
"true"
/>
<capability name=
"activexcontrols"
value=
"true"
/>
<capability name=
"backgroundsounds"
value=
"true"
/>
<capability name=
"cookies"
value=
"true"
/>
<capability name=
"frames"
value=
"true"
/>
<capability name=
"javaapplets"
value=
"true"
/>
<capability name=
"supportsCallback"
value=
"true"
/>
<capability name=
"supportsFileUpload"
value=
"true"
/>
<capability name=
"supportsMultilineTextBoxDisplay"
value=
"true"
/>
<capability name=
"supportsMaintainScrollPositionOnPostback"
value=
"true"
/>
<capability name=
"supportsVCard"
value=
"true"
/>
<capability name=
"supportsXmlHttp"
value=
"true"
/>
<capability name=
"tables"
value=
"true"
/>
<capability name=
"supportsAccessKeyAttribute"
value=
"true"
/>
<capability name=
"tagwriter"
value=
"System.Web.UI.HtmlTextWriter"
/>
<capability name=
"vbscript"
value=
"true"
/>
</capabilities>
</browser>
</browsers>
自己在项目中添加的文件：
<browsers>
<browser id="IE11" parentID="Mozilla">
<identification>
<userAgent match="Trident\/7.0; rv:(?'version'(?'major'\d+)(\.(?'minor'\d+)?)(?'letters'\w*))(?'extra'[^)]*)" />
<userAgent nonMatch="IEMobile" />
</identification>
<capture>
<userAgent match="Trident/(?'layoutVersion'\d+)" />
</capture>
<capabilities>
<capability name="browser" value="IE" />
<capability name="layoutEngine" value="Trident" />
<capability name="layoutEngineVersion" value="${layoutVersion}" />
<capability name="extra" value="${extra}" />
<capability name="isColor" value="true" />
<capability name="letters" value="${letters}" />
<capability name="majorversion" value="${major}" />
<capability name="minorversion" value="${minor}" />
<capability name="screenBitDepth" value="8" />
<capability name="type" value="IE${major}" />
<capability name="version" value="${version}" />
</capabilities>
</browser>
<!-- Mozilla/5.0 (Windows NT 6.3; Trident/7.0; rv:11,0) like Gecko -->
<browser id="IE110" parentID="IE11">
<identification>
<capability name="majorversion" match="11" />
</identification>
<capabilities>
<capability name="ecmascriptversion" value="3.0" />
<capability name="jscriptversion" value="5.6" />
<capability name="javascript" value="true" />
<capability name="javascriptversion" value="1.5" />
<capability name="msdomversion" value="${majorversion}.${minorversion}" />
<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" />
</capabilities>
</browser>
</browsers>