Ajax error: 'sys 'does not define a solution.

Since Ajax v1.0.61025 is re-installed,ProgramError: 'sys 'undefined information.
Finally, the problem is found.
First, set the configuration in Web. config:
..............
<Httphandlers>
<Remove verb = "*" Path = "*. asmx"/>
<Add verb = "*" Path = "*. asmx "Validate =" false "type =" Microsoft. web. script. services. scripthandlerfactory, Microsoft. web. extensions, version = 1.0.61025.0, culture = neutral, publickeytoken = 31bf3856ad364e35 "/>
<Add verb = "get" Path = "scriptresource. axd" type = "Microsoft. Web. Handlers. scriptresourcehandler" Validate = "false"/>
</Httphandlers>
<Compilation DEBUG = "true">
<Assemblies>
<Add Assembly = "Microsoft. Web. Extensions, version = 1.0.61025.0, culture = neutral, publickeytoken = 31bf3856ad364e35"/>
</Assemblies>
</Compilation>

............

Recompile and run.

If an error still persists after web. config is configured, set <asp: scriptmanager id = "scriptmanager1" runat = "server" asyncpostbacktimeout = "200">
</ASP: scriptmanager>
Followed by the <form> flag.

Note: Only one scriptmanager can be found on a page.