<p>Now that &xep0004; has been finalized, several uses of jabber:x:data forms have been put on the standards track, including &xep0045;. These protocols typically need a way to gather data from both humans (using a GUI format) and computer processes (using a pre-defined but flexible format).</p>
<p>The 'jabber:x:data' namespace provides an adequate mechanism for both of these uses, as long as computer processes can rely on the var="" names on a particular type of form.</p>
<p>This document proposes a specific mechanism for the ®ISTRAR; to standardize these form field variable names. Thus this document enables existing clients to process forms as they have to this point, but enables protocol authors to specify a mechanism for non-GUI processors of those forms to determine the semantic meanings of those forms.</p>
<li>Forms must continue to be presentable to humans for data entry.</li>
<li>Jabber clients that know how to process generic jabber:x:data messages must be supported; the basic format of jabber:x:data must not change.</li>
<li>If a form type is used in the context of a standards-track protocol, it should be standardized and registered; however, there is no requirement that all form types must be registered (e.g., form types used in custom applications).</li>
<li>If a form type is standardized and registered, field names used in the context of that form type must either be standardized as well or else be clearly labeled as unregistered.</li>
<li>Forms that are not directed <em>to</em> an entity must be able to traverse the entity (e.g., a form sent to a MUC room, intended for the participants of the room, and not the room itself).</li>
<li>Forms must continue to be flexible for implementations; unknown future expansion fields must not be limited.</li>
<li>The chosen approach must work for forms embedded in messages as well as in IQs.</li>
<p>Within Jabber, namespaces are used to scope data that conforms to a schema (often data that extends the core protocol in some fashion). In addition, namespaces can also provide context for the field variable names used in jabber:x:data forms and reports. This proposal makes that link explicit by defining a mechanism for linking a namespace name with a form and the field names and types used in that form. Specifically, the namespace name is specified in the form as the value of a hidden variable called "FORM_TYPE".</p>
</section2>
<section2topic='Whether to Register'anchor='approach-register'>
<li>If the field name is defined by the relevant XEP or by registration, the field name MUST be registered with the XMPP Registrar and MAY have any name (except a name that begins with "x-"), subject to approval by the XMPP Registrar.</li>
<p>In the following example, the FORM_TYPE is 'http://jabber.org/protocol/pubsub', and all of the fields whose var names start with "pubsub#" would be registered with the XMPP Registrar, associated with that namespace.</p>
<section2topic='Message with Bad Field'anchor='usecases-badfield'>
<p>When a FORM_TYPE is specified correctly, and an unknown field is found whose name does not start with "x-", a receiver MAY respond with an "Not Acceptable" error.</p>
<examplecaption='Message with bad field'><