IE11出现“__doPostBack未定义”的解决办法。

方法一:浏览器设置成兼容模式，这个是超级掩耳盗铃方法，你就没想过其他人也会出这个问题。

方法二、安装服务器版的.Net40的补丁。http://download.****.net/detail/5653325/6642051

方法三、点击VS的工具菜单--》库程序包管理器--》程序包管理器控制台（如果没有“库程序包管理器”的菜单，就先点那个“扩展管理器”，安装一个叫“NuGet程序包管理器”，然后就会有了。），点击后下面会出现一个连接PowerShell的控制台，等控制台加载完毕后输入

install-package App_BrowsersUpdate 回车

等待安装完成后，网站根目录下面会出现一个App_BrowsersUpdate目录。然后再访问就不会出现“__doPostBack未定义”的错误提示了。

使用VS2010的话，根目录会出现App_Browsers这个目录，如果使用IE11的还是会出现“__doPostBack未定义”的错误提示了。

打开App_Browsers=》ie.browser=》

加上如下这段代码：

<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>