File formats that require browser plug-ins or special software limit accessibility to information on the web in a number of ways:
- Installation of the necessary software may not be easy or even possible because users:
- May not be authorized or allowed to download software (for instance, if they work for some state agencies or they use library or school computers)
- May not be comfortable downloading and installing new software or may be concerned about computer viruses
- May encounter installation problems and software conflicts
- The alternative file format itself may be inaccessible to many users. For example, audio and video files without text equivalents are useless to some disabled users (see Section 3, Graphics and Sound).
- Most major search engines only index HTML pages. 1 These search engines are an important way for users to find information on the web.
- State agencies are strongly encouraged to publish all web pages in HTML whenever possible.
- There are times when a business need exists to provide information in an alternative format. In these situations:
- Choose a format that is consistent with the open standards specified in the Commonwealth's Enterprise Architecture. (Please consult the latest version of the Enterprise Technical Reference Model: Service Oriented Architecture posted on ITD's website.)
- Provide links to free, non-proprietary, readers or viewers, when appropriate.
- Provide an HTML version of the information in addition to the original format whenever possible.
The Portable Document Format (PDF) file format is often used for the following business reasons:
- Documents need to match a printed version (signed documents, for example).
- Lengthy documents cannot be broken down easily into web pages because of readability and printing limitations (manuals or instructions, for example).
- The integrity of the document format must be preserved for historical or regulatory reasons.
When documents are published in PDF, the following are implementation options in order of preference:
- Create a PDF that is optimized (resulting in less download time) and accessible. Provide navigation aids within the PDF (for example, a Table of Contents, bookmarks, "Back to" buttons) as well as navigation back to the appropriate website page. In addition to the PDF, provide the information in HTML or another accessible format.
- Indicate that the link is to a PDF file format.
- Identify the alternative format provided, and explain its use (for example, "Please view the HTML version of this document.")
Note: Content authors who produce PDF documents for publishing on the web must familiarize themselves with best practices for optimizing PDFs for disabled users. Refer to the Web Accessibility Resources for information on making documents accessible.
- When option 1 is not possible, use an optimized and accessible PDF, and provide a link to the agency web accessibility statement (see Section 6) that provides contact information for obtaining an accessible version of the document for those experiencing difficulties with the PDF file.
Note: Choosing option 2, rather than option 1, means that disabled users do not in fact have equal access to the information that the state agency is providing on the web. This is an option of last resort, and should never be used as a standard practice. Every effort should be made (and documented) to publish all web content in a format that will be accessible to all.
Refer to support materials on creating accessible documents, on websites such as:
1 As of the release of version 2.0 of the Commonwealth Web Accessibility Standards, the Mass.Gov Search function only indexes HTML pages.