article by Frank Hellenkamp / Sebastian Reinhold
HTML forms: Easy and difficult at the same time
HTML-Forms are simple to write – but to do it in a good way and to make them comfortable to use is not an easy task.
There are a few things you will have to do again and again:
Write the HTML for the form itself
Style the form in the right way
Validate the data in the browser (optional)
Validate the data on the server (never optional - don't forget!)
Additionally make sure the user don't have to fight with the browser e.g. strange messages about "resending" data on reloading the page and using back- and forward-buttons.