Farfalla Project: Browser-Based Accessibility Solutions
Andrea Mangiatordi, Harpreet Singh Sareen · 2011 · Proceedings of the International Cross-Disciplinary Conference on Web Accessibility (W4A) · doi:10.1145/1969289.1969317
Summary
This paper presents Farfalla, a free and open-source project from the University of Milano Bicocca that provides cloud-based assistive technology through the browser, eliminating the need for locally installed software. The core insight is that traditional AT is deeply tied to specific operating systems and devices, creating problems for users who access computers they don't control (libraries, workplaces, schools) or who lack administrative privileges to install software. Farfalla works by injecting a JavaScript file into web pages — either through a bookmarklet that users save to their favorites bar, a Greasemonkey-compatible userscript, or code that website owners embed directly. The injected script communicates with a remote server via AJAX and JSON to load user preferences and activate selected plugins. Plugins are organized into profiles (pre-defined combinations suited to different needs), with the frontend built on jQuery and jQuery-UI for cross-browser compatibility and the backend using CakePHP with MySQL.
Key findings
The plugin library at publication included: a magnifier (renders elements under the mouse enlarged with white-on-black high contrast), a virtual keyboard (appears only when clicking textarea or input fields), font-size adjustment, high-contrast mode for all page elements, an enlarged mouse pointer (with distinct cursors for text and links), and text-to-speech (with both mouse-click and arrow-key selection modes). Two plugins were under development: AddAlt ("Alternative Text in the Cloud"), which allows any user to contribute alt text for images they encounter — overlaying a button on images that opens an authoring interface, storing image URL and suggested alt text in a shared database, then dynamically adding those crowd-contributed descriptions on subsequent visits; and Dasher integration, a Java-based writing aid that enables text input using only a pointing device at speeds faster than an onscreen keyboard. The system could be deployed in three ways: a live demo on the project website, a bookmarklet activatable on any page, or a Greasemonkey userscript installable as a browser plugin. The entire source code was available on Gitorious.
Relevance
Farfalla represents an early vision of cloud-based assistive technology that anticipated several trends: the shift from installed AT to browser-based solutions, the idea of accessibility as a service deployed alongside content rather than as separate end-user software, and the crowdsourced accessibility repair model (AddAlt) later seen in projects like IBM's Social Accessibility. The no-installation approach directly addresses the access gap for users on shared or locked-down computers — a common situation in developing countries, libraries, and educational institutions. The plugin architecture allowing website owners to embed Farfalla directly prefigured modern accessibility overlay products, though Farfalla's open-source, non-commercial model and focus on genuine AT functionality (magnification, TTS, virtual keyboard) distinguished it from the controversial commercial overlays that followed. The project's main limitations were its early-stage profile system (only pre-defined profiles, no user customization yet) and browser compatibility issues with Safari and Internet Explorer.
Tags: assistive technology · cloud computing · web accessibility · accessibility tools · browser extension · low vision · text-to-speech · crowdsourcing · open source