XForms - Implementation Technologies Compared

Implementation Technologies Compared

FormFaces, AJAXForms, XSLTForms, betterFORM, Chiba, Orbeon and Smartsite Forms are based on Ajax technology. The amount of server-side and client-side processing varies between these implementations. For example, Ubiquity XForms, FormFaces and XSLTForms provide 100% XForms client-side processing and data model updates via pure Ajax processing on the XForms standard. The others use server-side Java/.NET XForms processing transcoding to Ajax markup prior to delivering the content to the browser. Both techniques can work across browsers. Each implementation is significantly different with respect to dependencies, scalability, performance, licensing, maturity, network traffic, offline capability, and cross browser compatibility. System architects should evaluate these constraints against their need to determine potential risks and objectives.

Plugins like FormsPlayer and other client-side technology can have some benefits as well: because they integrate themselves into the browser, they will work with existing server architectures, can be more responsive, and require fewer server fetches.

The tradeoff between server-side and client plug-in solutions is where the software is maintained; either each client must install the required plug-in, or the server architecture must change to accommodate the XForms transcoder engine language technology. It is in theory possible to mix both of these solutions, for instance testing the browser for a client-side XForms implementation and serving native XForms in that case, and defaulting to a server solution in other cases.

Ubiquity XForms, FormFaces and XSLTForms provide a "zero software" solution on either the client or server: no new software needs to be installed on the client and the solution can be used in conjunction with any server-side architecture. This is possible because FormFaces and Ubiquity XForms are written 100% in Ajax and because XSLTForms is written in XSLT and in Ajax. The tradeoff is that compared to other solutions, more code is initially downloaded to the client (code can be cached on the client), and FormFaces does not yet support XML Schema validation. Furthermore, XForms submissions with replace "all" behaviour will typically not result in true page replacements and therefore break the normal back button behaviour.