accesskey _ mod _ content


No, it is not strictly necessary. Validate the grammatical correctness of the code is not a prerequisite in WCAG 2.0, although it is highly recommended to ensure compatibility of the same between different browsers.

As a minimum requirement, the code of the pages must be subject to prosecution. In other words, there should be no errors in the code that can cause problems of interpretation in all different browsers and user applications.

If the code is to be subject to prosecution must be performed at least be well trained. The opening and closing tags must remain the specification. There must be closing tags for all elements that require and should not exist for those elements on which prohibited. tags of opening and closing nested must be properly for all elements. The value of the attributes must be quoted correctly and not be repeated in those attributes values that require a single value (for example, the id).

If this minimizes the risk that the code is processed incorrectly by any user application. However, the best option and is more advisable always validate the code according to the formal grammar used. The main advantage of validating the code is the elimination of all ambiguities that may arise for the use of incorrect.

If during the validation of a page, the HTML validator returns mistakes of the type cannot generate system identifier for general entity, are due to that in order to use special characters in the URL must make use of its entities. In the case of the character & , the corresponding state is & .

Code example



The most accessible and recommended to make a redirection is that in a transparent manner to the user. This can be used on the side of redirections server instead of using redirects on the client. If you use client redirects They must be immediate, no time limit, to be transparent to users.

In the case of redirections of server will have to configure It properly to indicate the status code HTTP suitable (301). For example, on the Apache web server uses the directive redirect.

Example of directive in apache
redirect/page _ antigua.html/page _ nueva.html


It is always preferable to use server redirects. However, if there is a need to do redirections from client (for example, because it does not have access to the server configuration) Be snapshots to be transparent to users.

Code example


No, it is not mandatory. The accessibility standards do not require a certain grammar use. The Only requirement is that the code is correct so as to ensure the compatibility between different browsers and support outputs. Cumpliéndo the foregoing, may be used both as xHTML, HTML5 as earlier versions of HTML.

With regard to what kind of grammar using, and although it is not a requirement, it is recommended to use strict grammars.

For a PDF document deemed accessible must be labeled and structured, with alternatives to all textual element, with marked language and order appropriate reading and, in the case to be protected, with the security council.

To achieve this marking accessible there are two ways:

  • Create a separate accessible through a word processor and export to PDF labelling (not all tools allow this export).
  • Export to PDF document and subsequently tag them manually (through Adobe Acrobat Professional).

In addition, it is necessary to provide in the pages which includes links to PDF documents, an outline or a summary format (X) HTML + CSS accessible, of the information may be contained in the PDF.

For further information on the process of building PDF accessible you can consult the "accessibility guide in PDF Documents ” available in the section in the area of documentation.