The Dogma W4 - details and explanation

Ad 6. The convey

Author must assume, that a document may be presented on any possible appliance (both graphical and text browsers, print, aural output, display of handheld or phone etc.). The document must must be usable on all of them - its conveyance must not be available with only some of those appliances.

Every piece of information communicated in a web document must be legible in a text format.

Text is the only type of information, which can be interpreted by all applicable devices. Every information conveyed by the document must therefore available in a text format. When the document contains information in another form (picture, object etc.), there must be present a text version, at least as an alternative source.

The document's statement may contain only:

The alternative text form is meant to be the description written in alt attribute of the appropriate tag or link to the document providing the information in text form.

Details: The pictures

Pictures in non-standard format (not JPG, GIF nor PNG) may only be referenced when their alternative form in standard format is available.

Pictures, which contain no information (they are only for decorative purposes) or whose purpose is only to express text, must not be present in the document - they may however be added by another ways (CSS, Javascript etc.).

Details: The scripts

The text inserted by the script must not be a part of information provided by the document. Otherwise the user must be provided with an alternative version, which does not need script execution.

Details: The external files

If the user is offered an information in the external files, which is not type of TXT, RTF nor PDF, he must be provided with an alternative in widely accessible format. For example a table in XLS format may be published for download only when its alternative version in (X)HTML, text file or in PDF is present.

The links to files for download should be supplied with information about file size, type of the file and an application used for processing such file.

If the file contains no information and is meant to be used on particular devices or platform (programs and data files for download), the user must be warned of this, and it must be stated for which platform and device this file is designated.