Rationale

• Provide form author with more flexibility to indicate
• required fields
• visited fields
• invalid fields
• Currently, CSS gives some control, but not full control.
  

Ideas

• Use XBL as template language to provide full flexibility?
• Orbeon provides default implementation which satisfies most case

Issues to solve

• "visited" property must be handled better
• either natively
• or using custom MIPs
• or other solution
• need ability to better control notion of "visit"
• IE 6 selectors are weak so might need more combined classe produced to cover all cases
  

Example XBL code

<xbl:binding element="fr|input">
    <xbl:resources>
        <!-- Style determines visibility of images -->
        <xbl:style>
            ...
        </xbl:style>
    </xbl:resources>
    <xbl:template>
        <!-- Group will have MIP classes -->
        <xforms:group xbl:attr="ref bind model context">
            <xhtml:img class="fr-required-field" src="..." alt="..."/>
            <xhtml:img class="fr-required-visited-field" src="..." alt="..."/>
            <!-- Control binds to . -->
            <xforms:input ref="." xbl:attr="...">
                <xbl:content includes="xforms|label, xforms|hint, xforms|alert, xforms|help"/>
            </xforms:input>
        </xforms:group>
    </xbl:template>
</xbl:binding>