Introduction

• Rich web applications make extensive use of Javascript, and this is expensive to develop and expensive to maintain
• XForms-Tiny defines incremental improvements to HTML leveraging the XForms architecture to reduce the cost of deploying forms-based web applications
  • Simple declarative expressions in field attribute values
  • Much easier to maintain than when buried within complex scripts
• Web developers who have existing forms assets who are reaching the limits of what they can do with HTML forms can now take incremental advantage of the XForms architecture without first having to switch to XML
• Convenient growth path to rich capabilities of full XForms when needed
  • Export data model, constraints and controls to XForms syntax
  • Can be used for server-side data validation

XForms-Tiny Standards Work

• XForms-Tiny is aimed at authors and authoring tools for use with text/html
• Doesn't require, but doesn't preclude, native implementations in browsers. This allows it to be widely deployed today without waiting for new browser releases
  • Open source script library that works on IE6, IE7, Firefox, Safari, Konqueror, Opera desktop, Opera Mobile 8.6 and NetFront 3.4
  • Only 6 KBytes download when compressed
• First Public Working Draft expected Q1 2007
  • a product of the W3C Forms Working Group
  • to be standardized in coordination with new HTML Working Group
  • draws upon ideas in Web Forms 2.0 proposal
  • uses extensible ECMAScript syntax for expressions
    • familiar to authors and convenient for implementors
    • Can take advantage of author defined functions
  • library will track changes in specification
  • enable heterogeneous mix of native and non-native implementations

XForms-Tiny Features

• Small set of new attributes and attribute values
  • Simple expressions for validating field values and spread-sheet like formulae for computed fields
  • Repeating groups of fields, e.g. for line items in purchase order or expense claim
  • Suppression of irrelevant parts of forms and context dependent control over which fields must be filled out
  • Avoids the need for writing client-side code
• Demonstrations of individual features
  • Data types, e.g. number and date
  • Contraining field values with regular expressions
  • Calculated fields using spreadsheet-like formulae
  • Min and max values
  • Range controls
  • Validation expressions
  • Required fields
  • Relevant groups of fields
  • Repeating fieldsets
  • Initializing fieldsets
  • Using radio buttons to determine relevancy
  • Calculations involving selection fields
  • Calculations involving checkboxes
  • Referring to fields within named fieldsets
  • Editable selection lists (combo boxes)
  • Export to XForms syntax

Further work

I am planning on updating the library to track the associated specification work in the W3C Forms working group. Currently I am expecting to work on the following:

• emulating the XForms incremental mode whereby expressions are evaluated on every keystroke rather than waiting for the onchanged event
• providing script interfaces for inserting/deleting/moving "rows" in repeating node sets (fieldset with repeat-number) and some kind of customisable UI for driving these
• providing mobile friendly presentations for repeating node sets, e.g. showing one "row" at a time with the fields and labels arranged in a single column and the provision of buttons to move between "rows"
• support for using Ajax to load/save form data
• support for a wider range of mobile browsers