Unrecognized attribute 'targetFramework'. Note that attribute names are case-sensitive.

调试网站时，异常出现：Unrecognized attribute 'targetFramework'. Note that attribute names are case-sensitive.

Server Error in '/' Application.

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Configuration Error

Description: An error occurred during the processing of a configuration file required to service this request. Please review the specific error details below and modify your configuration file appropriately.

Parser Error Message:
Unrecognized attribute 'targetFramework'. Note that attribute names are
case-sensitive.

Source Error:

Line 15:   </connectionStrings>
Line 16:   <system.web>
Line 17:     <compilation targetFramework="4.5" />
Line 18:   </system.web>
Line 19:   <runtime>

Source
File: D:\Sites\xxxxxx\web.config    Line: 17

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Version Information: Microsoft .NET Framework Version:2.0.50727.5420;
ASP.NET Version:2.0.50727.5420

检查上面的异常信息，Insus.NET发现开发的项目是ASP.NET MVC是在.NET Framework 4.0的环境下运行的。但在最后一个即显示的是.NET 2.0

解决方法：