¡¾ÀíÂÛĽ¿Î¡¿ÕÅÖ¾Ã÷£ººËÐÄÊÇÒª¼ÓÇ¿µ³µÄÁìµ¼

W3C Forms Working Group

This document is being put together by the members of the W3C XForms Working Group as a repository of Frequently Asked Questions about XForms 1.0.

Please send suggestions or comments about this FAQ to www-forms@w3.org (archives), including the word FAQ in the subject line.

Table of Contents

• What are the advantages of XForms?
• What can I do with XForms that I can't do with old HTML Forms?
• Is XForms more complicated than HTML Forms?
• Will we have to wait for new browsers?
• Will XForms work on PDAs and mobile phones?
• What servers (currently) support XForms?
• Who is backing XForms?
• Aren't other companies also coming with new forms technologies too?
• What other resources are there?

What are the advantages of XForms?

Here are the primary benefits:

XForms improves the user experience

XForms has been designed to allow much to be checked by the browser, such as types of fields being filled in, that a particular field is required, or that one date is later than another. This reduces the need for round trips to the server or for extensive script-based solutions, and improves the user experience by giving immediate feedback to what is being filled in.

It is XML, and it can submit XML

XForms is properly integrated into XML: it is in XML, the data it collects in the form is XML, it can load external XML documents as initial data, and can submit the results as XML. By including the user in the XML pipeline, it at last means you can have end-to-end XML, right up to the user's desktop.

It combines existing XML technologies

Rather than reinventing the wheel, XForms uses a number of existing XML technologies, such as XPath for addressing and calculating values, and XML Schema for defining data types. This has a dual benefit: ease of learning for people who already know these technologies, and the ability for implementors to use off-the-shelf components to build their systems.

It is device independent

The same form can be delivered without change to a traditional browser, a PDA, a mobile phone, a voice browser, and even some more exotic emerging clients such as an Instant Messenger. This greatly eases providing forms to a wide audience, since forms only need to be authored once.

It is easier to author complicated forms

Because XForms uses declarative markup to declare properties of values, and to build relationships between values, it is much easier for the author to create complicated, adaptive, forms, without having to resort to scripting.

It is internationalized

Because the data submitted is XML, it is properly internationalized.

It is accessible

XForms has been designed so that it will work equally well with accessible technologies (for instance for blind users) as with traditional visual browsers.

What can I do with XForms that I can't do with old HTML Forms?

XForms can do everything that HTML Forms can do, and then some. In particular XForms lets you:

• Check data values while the user is typing them in.
• Indicate that certain fields are required, and that the form cannot be submitted without them.
• Submit forms data as XML.
• Integrate with Web services, for instance by using SOAP and XML RPC.
• Submit the same form to different servers (for instance a search string to different search engines).
• Save and restore values to and from a file.
• Use the result of a submit as input to a further form.
• Get the initial data for a form from an external document.
• Calculate submitted values from other values.
• Constrain values in certain ways, such as requiring them to be in a certain range.
• Build 'shopping basket' and 'wizard' style forms without needing to resort to scripting.

Is XForms more complicated than HTML Forms?

No. The XForms Recommendation may make it look complicated, but it is not a tutorial on XForms; it is addressed to implementors who need to know exact details about how to implement XForms, and so is very detailed.

The same form written in HTML Forms and XForms looks pretty much the same. It is when you start to design forms that HTML wasn't designed to handle that XForms starts to become much simpler. So XForms contains things that HTML Forms doesn't, but that is in order to make forms creation simpler. See XForms for HTML Authors for examples.

Will we have to wait for new browsers?

No. There are already several implementations that let you use XForms with existing browsers, either with plugins or by transforming the forms at the server, as well as a number of browsers that implement XForms natively.

There is a list of XForms Implementations that contains details of many of these implementations; an editorial review including screen shots of some of them, can be found at xml.com.

Will XForms work on PDAs and mobile phones?

At the time of writing XForms has been demonstrated on PDAs and mobile phones using proxies, using the same techniques that are often used to present web content on smaller devices. We anticipate that native XForms clients will appear on mobile devices soon.

What servers (currently) support XForms?

All of them! XForms has several new submission methods compared with HTML Forms, but these are all standard HTTP methods for sending data over the network. XForms can use 'PUT' to put data to a server, can talk to a SOAP or XML RPC server, but also supports legacy formats allowing forms to work with all existing forms servers.

Who is backing XForms?

The XForms working group that created XForms contains representatives from many major computing companies, see the press-release and testimonials about XForms for details. On top of this there are a large number of implementations emerging. In fact XForms is the most-implemented W3C specification ever at this stage in its life-cycle.

Some large user populations are beginning to emerge, including the British Government's e-government initiative, one country's tax service, and a country's insurance industry.

Aren't other companies also coming with new forms technologies too?

That's right. Forms were the basis of the e-commerce revolution and they are still a hot topic! However, the many companies backing XForms believe that there are advantages in using a non-proprietary technology that is based on common standards, and not tied to a single vendor. It means a wealth of user agents on a variety of platforms. Furthermore, we believe that once you have appreciated the advantages of the XForms approach -- authoring once for multiple platforms, integration in XML, ability to 'edit' external XML documents -- you will want no other!

What other resources are there?

The XForms home page is a good source of information about XForms.

There are books about XForms appearing, and a search for "XForms" at any well known online bookstore will reveal them.

There is an introduction to XForms for HTML Authors.