Markup language validating system
This implies light-on-dark or dark-on-light: colour contrasts are insufficient to cater for monochrome displays or colour-blind readers.
Note that this implies that authors setting a text colour MUST also set the corresponding background, and vice versa.
anyone working in an environment where you might reasonably be expected to know more than your Employer or Client).
It is assumed that readers already have a general working knowledge of HTML, such as might be acquired through appropriate training or experience.
These Web Authoring standards should be seen as complementary to the HTML Markup standards published by W3C.
These standards shall apply to all webpages created to be accessible to the general public, except as follows: Professional Web developers working for or on behalf of any organisation whose business is not the Web itself (i.e.
Every major path through the program SHALL be represented by such a sample output page, and tested with the same attention as the software itself.
Dynamic pages which include a user's input may be beyond the author's control.
Standards to be applied to the development of software associated with dynamic webpages are assumed to derive from existing PSS05 or equivalent standards where appropriate, and are outside the scope of this document.
These languages are defined by technical specifications, which usually include a machine-readable formal grammar.
The act of checking a document against these constraints is called validation, and this is what the W3C Markup Validation Tool does.
HTML constructs which render a document difficult to read due to known defects in popular browsers SHOULD be avoided, regardless of the construct's validity in strict HTML.
All of the guidelines in this section are advisory.
This validator can process documents written in most markup languages.