sometimes it's needed to check whether there are multiple same
modules in the current page or not to keep one version of the
module or some other checks.

HttpCookie is a very good way to store small amount of data
in asp.net application/website.you can access cookie value in
any page once set in a page.cookie can stay for long time in the
user's computer.

implementing video in asp.net or php pages is a great thing!.
there are a lot of players are available in web to show
video free.

Today ajax is being a common part in most large website and
application.user loves the way everything done without page
refresh and website's with ajax implemented is getting higher
popularity.in the following i showed how to use ajax in asp.net
web page.you can use in php too -

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.

It's a good practice to show orange border when you set focus to textbox.
also the border will stay for some seconds.this way user know
that they have to do task on that textbox.

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.

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

Gravatar.com is used to store one's avatar image according to email.
then if you comment in any application using your that email address
where gravatar image has been programmed then your avatar image will
be displayed in the application.

asp.net routing is easy to use for rewriting any url.

if you have a url like wwww.aspdotnetsite.com/Projects?user=username.
but if you want to have it in short name for marketing or for anything
you want like this is the resulting url -
wwww.aspdotnetsite.com/Projects/username