System.Net namespace is for dealing with networking.It
is concerned with operations like downloading, uploading
files,making requests by http protocols.

you will need to access html elements from asp.net
code behind file.i show you how to access widely used
html textarea element from code behind file -

It's a very common requirement to create different types of button and
it's click event handler dynamically in asp.net application.

using SMO classes one can backup a sql server database
in .bak extension.It's a programming approach to backup
database.there are other ways but using SMO classes it
is efficient and error free.

to create and use the object instances on remote machines .Net remoting
is used,without any DCOM involved.

this article will cover .net remoting with common hosting method in IIS.

It's a very common requirement to show hint in textbox when empty
and when textbox gets focus hint goes away.now a days many websites
implemented showing hint.there are many ways to do that by jquery.

you may want to get the asp.net control's or html element's
id when clicked or other events fired for that element.
It can be done in many ways using jquery or simple javascript.