The Dogma W4 - details and explanation

Ad 10. The extensions

All code affecting the a web document's presentation must be placed in external files and linked from the head of the document.

Definition of styles in <style> tags are forbidden, they may only contain @import statements. The use of style="" attribute is forbidden.

It is not allowed to place script codes into the <script> tag. Scripts must be located in external file and referenced from the document. The only exception are third parties' codes, which can not be placed into the header (i.e. advertisement codes etc.). The code in tag's attributes (i.e. onmouseover="") must be brief and simple.

No web document should depend on a resource for its proper rendering which can be disabled or uninstalled at the user's preference, ...

Absence of sufficient support of any extension (disabled or unavailable pictures, disabled scripts or styles, disabled cookies, disabled plug-in etc.) must not cause limitation of document's usability. Document extensions (scripts, CSS, objects etc.) must not generate nor import data with any informational value, unless they are alternatively available without using such extensions.

When the document is to contain elements, which are senseless without functional extension (script, installed plug-in) (i.e. navigation buttons, dynamical menus etc.), they must be created as a result of a script processing (adding/modifying existing elements). When author defines the document layout, expecting script functionality, such style must be added by that script after verifying its functionality.

... or which requires the user to obtain software not ordinarily available as part of their web browsing environment.

The document must not require an user to install any add-on to extend browser's functionality. When the document contains extension, which will not work without such add-on, this extension must be disabled and its convey must be offered in an alternative way (see also The convey). Automatic software installation, even if supported by browser, is absolutely forbidden.

Furthermore, the user's browsing preferences should not be changed or disregarded by the code or markup present in the document.

Used script (or other document extension) must not by any means restrict using end device. Above all it is forbidden to disable buttons or menus in browser, disable changing the size or closing the window with document, deny user to choose own fonts, colors or styles etc.

Script must not change setting of user's preferences without user's request. Every action performed outside the document, such as changing the window's size and position, closing the window or terminating application, saving bookmark etc. are only allowed as a consequence of user's action, which he had been forewarned of (see also The links).