【转】asp.net 项目在 IE 11 下出现 “__doPostBack”未定义 的解决办法

最近我们运营的网站有用户反馈在 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。

<!--
可在 <windir>Microsoft.NETFramework<ver>CONFIGBrowsers 中找到现有的浏览器定义
-->
<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>