What is the .axd file?

Hello all,

I config my web.config and add a entry :

<add verb="*" path="GoogleSiteMap.axd" type="DNN.Modules.GoogleSiteMap.GoogleSiteMapHandler" />

This will generate a XML file for the sitemap. I created a class library and added the compiled dll to the bin folder of my website project.

At the first time, there were some errores, because I added a XMLElement before the start tag of the XML file, sincethe XML file can't correctly display.

So I modified the code in the library and recompiled it. Then I added the dll to the bin folder again, I'm absolutely sure the format of the XML file is correct, but the errores were still there.

 

I wonder what the .axd is, how it implements, so I can find the way to fix the errores.
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