A basic request looks like:
GET /default.aspx HTTP/1.1 Host: www.contoso.com
or
GET /default.aspx?Id=123&color=blue HTTP/1.1 Host: www.contoso.com
or
POST /default.aspx HTTP/1.1 Host: www.contoso.com Id=123&color=blue
The response will look more like:
HTTP/1.1 200 OK Server: Microsoft-IIS/6.0 Content-Type: text/html Content-Length:68 <html>....</html>