Modify your web. config file as follows!
<System. Web>
<! --
Set compilation DEBUG = "true" to insert the debugging symbol
Compiled pages. However, this
Performance is affected, so this value is only available during development.
Set to true.
-->
<Compilation DEBUG = "true">
<Assemblies>
<Add Assembly = "system. Web. Extensions, version = 1.0.61025.0, culture = neutral, publickeytoken = 31bf3856ad364e35"/>
<Add Assembly = "system. Web. Extensions. Design, version = 1.0.61025.0, culture = neutral, publickeytoken = 31bf3856ad364e35"/>
<Add Assembly = "system. Design, version = 2.0.0.0, culture = neutral, publickeytoken = b03f5f7f11d50a3a"/>
<Add Assembly = "system. Drawing. Design, version = 2.0.0.0, culture = neutral, publickeytoken = b03f5f7f11d50a3a"/>
</Assemblies>
</Compilation>
<! --
In the <authentication> section, you can configure
Security Authentication mode,
To identify the user.
-->
<Httphandlers>
<Remove verb = "*" Path = "*. asmx"/>
<Add verb = "*" Path = "*. asmx "Validate =" false "type =" system. web. script. services. scripthandlerfactory, system. web. extensions, version = 1.0.61025.0, culture = neutral, publickeytoken = 31bf3856ad364e35 "/>
<Add verb = "*" Path = "* _ appservice. axd "Validate =" false "type =" system. web. script. services. scripthandlerfactory, system. web. extensions, version = 1.0.61025.0, culture = neutral, publickeytoken = 31bf3856ad364e35 "/>
<Add verb = "Get, head" Path = "scriptresource. axd "type =" system. web. handlers. scriptresourcehandler, system. web. extensions, version = 1.0.61025.0, culture = neutral, publickeytoken = 31bf3856ad364e35 "Validate =" false "/>
</Httphandlers>
<Authentication mode = "Windows"/>
<! --
If an unprocessed error occurs during request execution,
You can configure the corresponding processing steps in the <mermerrors> section. Specifically,
This section allows developers to configure
HTML error page to be displayed
To replace the error stack trace.
<Customerrors mode = "remoteonly" defaultredirect = "genericerrorpage.htm">
<Error statuscode = "403" Redirect = "noaccess.htm"/>
<Error statuscode = "404" Redirect = "filenotfound.htm"/>
</Customerrors>
-->
</System. Web>