IE10 SCRIPT5009: ‘__doPostBack’ is undefined

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There is apparently a bug in the browser definition files that shipped with .NET 2.0 and .NET 4. The definition files do not cater for IE10 as a browser version and hence defaults to a default definition which doesn’t support JavaScript.

Scott Hanselman has a very detailed writeup about this issue here: http://www.hanselman.com/blog/BugAndFixASPNETFailsToDetectIE10CausingDoPostBackIsUndefinedJavaScriptErrorOrMaintainFF5ScrollbarPosition.aspx

Scott proposes two solutions, with the first one being the recommended one:

1. Machine-wide fix
Download and install a hotfix on the server:

  • .Net 4 (http://support.microsoft.com/kb/2600088)
  • .Net 2 (http://support.microsoft.com/kb/2600100, http://support.microsoft.com/kb/2608565)

2. Site-only fix
Install the App_BrowsersUpdate package from NuGet into your website to import new ie and firefox browser definitions.

  • .Net 4 (http://nuget.org/List/Packages/App_BrowsersUpdate)
  • .Net 2 (http://nuget.org/List/Packages/App_BrowsersUpdate.net20)

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