Thank you for your post.
You've asked a loaded question....
Instant Web Publishing allows you to easily publish your database on the web. You don't need to modify your database file(s) or install any additional software. Any web browser can connect to your database to view, edit, add, sort, search, etc. The user interface resembles the desktop Filemaker Pro application. The web pages are dependent on the layouts and views defined in the database.
Custom Web Publishing gives you more control over the appearance and functionality of your published database. You can integrate you database with another website and controls how the data displays. With FileMaker, there is Custom Web Publishing with PHP, which provides an object-oriented PHP interface with Filemaker databases. There is a PHP Site Assistant that can generate a complete PHP website, or code PHP web pages yourself. There is also Custom Web Publishing with XML and XSLT. You would use XML data publishing to exchange FileMaker data with other websites and applications, and you can use XSLT stylesheets to integrate any subset of FileMaker data into other websites. There is also an XSLT Site Assistant to help generate XSLT stylesheets, or code the stylesheets yourself.
So, to answer your question, Instant Web Publishing allows the user to enter information directly into the database, or you could put the data into a temporary record, and when you click POST, the information is then transferred to the main database. With Custom Web Publishing using PHP, you would use very close to the same commands that you would use in a standard PHP web form.
If you need further clarification, please let me know.
Thank you for your response, TSGal. It sounds like what I am trying to accomplish might best be done with Custom Web Publishing. I've been able to get something set up quite easily using the php site assistant. What I've set up easily enters data into the Filemaker database from the php form. What I would like for it (the php form) to do is also send the data to an external address, using the typical html form action method = post. I will continue to investigate. Thanks.