How to solve Ajax type, sys undefined

I haven't moved Ajax for a long time. I suddenly encountered a lot of problems when I was using it. I was prompted that the type was undefined and SYS was undefined. In fact, I have encountered this problem before and solved it. I forgot it after a long time. I will write out the solution today and share it with you.
In fact, it is very simple. Now we need to add the following content in the <system. Web> section of Web. config:
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<Httphandlers>
<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>
<Httphandlers>
<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>

OK. The sys undefined problem is solved everywhere, but the WebService definition still exists. Create an empty Ajax enabled web application and observe the Web. config file to find the WebService configuration,
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<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 "/>
<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 "/>

Try to join the above node,
The test is successful. The complete configuration is as follows:

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<System. Web>
<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>
<System. Web>
<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>
Note: In <system. Web>
That's all.

this article from the csdn blog, reprinted please indicate the source: http://blog.csdn.net/jok127/archive/2009/12/03/4935004.aspx