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.

if we need some fields from different tables
temporarily in our software or application then

Often receiving "Fatal error: Allowed memory size of 33554432 bytes exhausted" when trying to upload an image with low mb file size. To solve this error, try to increase the memory allocated for PHP. For that you need to set the limit to 32MB, 64MB, 128MB or 256MB. However is based and depends upon your host provider.

it is easier to print part of page.the part of the page
may be under a div or panel.you can achieve this from code
behind file too as per requirement.here i showing only
in page lavel -

Do you have problem of receiving "Fatal error undefined function is_network_admin()" when you login to wordpress admin after updating WordPress.

It's a very logical requirement to validate user entered email
address before processing anything.in this way you will
never get a invalid email address when you do something
with email address like send email,etc.

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.