C# - Implement WebSockets From Scratch With The .NET 4 Framework (and Nothing Else)?

I want to build a simple chat app where people can go a url, type in a name and a message and click submit and it will basically show that message to everyone that is current connected.Firstly i would like to state i've had zero experience in sockets programming and the like. I'm simply a web 2.0 person building websites with css/html/js/ajax and backend i have asp.net on vb and sql server for database.So basically coming from an ajax background, i was wondering why do we even need to download any additional stuff to do web sockets? I mean in ajax i can simply create a asd.aspx file and use Response.Write(text) (text based on the input which are available through dissecting the url) and voila, the server side is done, all that's left is just to create new XMLHttpRequest and stuff in the client side.

So ok I'm not worried about the client side part of Web Sockets. but the server side part of web sockets is just difficult. so in the client side i have this: ws://localhost:8080/websocket. Is it true that it will work if is also an .aspx file as such: ws://localhost:8080/websocket.aspx ?I'm wondering so how do i continue from here? in Ajax i will supply parameters from client in the url as such: page.aspx?a=1&b=2 and do output in the server using Response.Write it's all clear but how do we do it in web sockets?