Entry #0002
If it doesn't find a matching record, it will (or at least in most cases, should) display an error message about the login details being incorrect. Another example is a Google search - you enter a search into the Google home page, your web-browser sends the search term off to Google's server, and it then begins looking for records in its database of websites that match (or are in some way related to) your search term, then send them back to you. You create server side scripts in any number of different languages... there's really no limit to what you can and can't use, so long as you're aware of the limitations of the particular web server you're hosting your pages on. Some examples of commonly used server side scripting languages are PHP (which is nice because it's very easy to find a good web host which supports PHP), Python (which is my personal favorite, because... well, I just like the language itself... I won't go into details why here - maybe that can be the topic of my next post), Perl, Ruby, and Microsoft's .Net languages. For that matter, I've seen people write CGI applications in low level languages like C/C++ - though I don't think I'm out of place calling those people masochists.