So, before we start learning about these things, here are a few external examples for you to consider:

• The Geometry Center's web site -- especially its
  Gallery of Interactive Geometry
• Some other web sites for science, such as the
  Frog Dissection Kit
• Any of the Web Search Engines -- such as
  Alta Vista for web pages, or
  411 for people & places
• Or, refresh your memory of forms by looking at any other forms-based pages that you are already familiar with. Feel free to share suggestions for these with your course-mates.

There are two things you need to be aware of with respect to forms & scripts:

• A script will do more than just generate a new page in your browser: it will also send information back to the server on which the form is being processed.
• In order to implement forms and/or other scripts, you may have to have special permission(s) from your local system administrator.
  (For example, those of you who have to send your pages off to someone else who posts them onto the the Web for you can, of course, use forms running on other systems but are not as likely to be able to implement your own ... you may be able to, but it's far from certain.)

Today's lesson, then, is split up (for historical reasons, irrelevant to this course, but I've not had time to redesign them) into three parts.

If you do have direct access and you can execute files from it [see note], then proceed:

1. Introducing CGI Scripts
2. Using Perl for CGI Scripts
3. Strategies for Using Scripts

Your Assignment: Guess what it is!

• If you are interested in implementing this sort of thing, and have the resources to do so, then try a small example.
• If you don't, please at least note my one request in the box above (and let me know if you have any problems running one of those little scripts...).
• If you're not sure, consider a couple of the simple examples at the end of this day's session, since they're more the sort of thing you might want to tackle on your first attempt (with something more on the order of the University of Minnesota Calculus Initiative, also linked there, as a longer-term goal).

[Note:] You may also have to try a few things and then, if you encounter problems, ask your webmaster / system administrator if your web server is set up to handle forms and scripts. If you know that anyone else has implemented these things on their pages at your site, then the odds are better that you will be able to do so too. If you do most of your local development on a Mac or PC, say, and then FTP files up to a Unix directory, then you also need to be able to set permission so files can be executed there (via chmod a+x *.cgi for example). If you use a Mac or Intel machine as your server, then you have to be able to permit script execution from your directory there.