Call C# code in ASP .NET when page loads

this help? http://social.msdn.microsoft.com/search/en-us?query=request

Then why wont you just use JSON enabled WCF service?

It is complicated if you want to run it exactly as you want. But you can also click-add-create it in vs. Ide will do everything for you. With json it is more demanding depending of how you want to call this service. If from .net site you can just add service reference from vs. If from example jQuery it is more complicated. Last time i was creating service i spend few hours just for configuring from which url this will be executed :) Write from where you would want to call this solution. Again wcf is complicated but also very powerful. So i think this wil be less error prone then your custom solution. For starter you have many things out of the box (authorization, serialization, deserialization, asp.net js scripts, data validation etc.) which in your solution you will have to make yourself. Yes you can also just add asp.net app to your iss. Delete html from default.aspx and in page load deserialize some parameter to object calculate something and return another object serialized as JSON with Response.Write It will be simple and it will work after 1 hour so again it depends what you want. But if it will have to be more complicated i would add WCF service just to learn how to do that. Its popular technology so experience with it will not hurt.