Facebook access token is needed whenever you access
facebook stream of page or profile, Graph api call to post
to facebook.there are many ways by which you can generate
access token.By the following way you can create short lived
access token for a user as well as extend it to long lived
token -

A CAPTCHA is a program which tells whether its user
is human or computers.

follow the steps below to add captcha in your web form
easily -

An extension that has a security issue or a flaw because of its poor coding can be said as a vulnerable joomla extension.

To protect your site affecting from the vulnerable issues follow the below steps:

I wanted paging for showing datalist items in pages.for
that i used pageddatasource.it's necessary very much.
following codes show how to add paging for datalist items -

how to insert data in specific joomla table? this way -

when you process credit card payment the two
most sensitive inputs are taken from customer
are card number and card security code.you
will want to verify that the data entered
is valid before processing credit card payment.

if you wanted to use jquery like for showing/hiding panel
when button clicked inside datalist itemtemplate then you
experienced that the action is repeated per item.