Forms
From PDF City
Forms in PDF are very similar to Web forms, built in HTML. They use the same kind of objects, such as text boxes, combo boxes, check boxes, radio buttons and command buttons. Also, they support javascript and http submit, to send data to some Web Server. However, PDF forms have some important differences from simple Web forms. Look at these ones:
1. Usually, HTML forms has its codes visible to the browser and, indirectly, to the user, who can, at the end, modify its contents. In fact, HTML forms cannot give the client any security, unless they are server-side signed.
2. HTML forms, as HTML pages, may differ from browser to browser, or from platform to platform. PDF forms have more fidelity to its original template, in terms of fonts, field sizes, borders, etc.
3. PDF forms can be client-side signed, with full integration to Windows CSP. This grants contents integrity, without the need for server mode security implemented service.
4. PDF forms can be saved, with or without form data (i.e. form fields contents), so that it do not need to be submitted immediately to the Web. In fact, it can be sent as an e-mail attachment or in a removable media or even be submitted in other circumstances.
5. PDF form data can be saved isolated, to be loaded afterwards. This permits to the user start filling the form at a time and finish it further.
6. PDF forms can be submitted as a whole, with al its contents, including attachments, pictures and other objects.
Although a PDF form can be made by simply aggregating fields to a existing PDF, by the use of a specific library, (for example, see the Java PDF Library), this can easily be done using Adobe Acrobat. Once composed, it can be published in a conventional Web site. The PDF form submit function is fully compatible with most web servers, so that programmers doesn’t have to modify their applications if they want to migrate form HTML.
Of course, there has to be installed a PDF reader in the workstation. Not all readers will fully support PDF forms. Even Adobe Reader must be up-to-date to perform all operations.
See more about PDF forms in Adobe’s web site and Planet PDF. There are also many distributable PDF based projects. You can find some of them at The Code Project.
