Guideline 1.3: Create content that can be presented in different ways (for example simpler layout ) without losing information or structure.
This guideline ensures that all information is available to all people. On inaccessible pages, certain information cannot be decoded by assistive technologies. When all information is programmatically exposed, assistive technologies will be able to present it in a different format depending on the user's needs.
1.3.1: Info and Relationships (Level A)
Information, structure, and relationships conveyed through presentation can be programmatically determined or are available in text. (Level A)
In simple terms, it is not enough that a page looks one way or another, it should also be coded the way it looks.
When you format a page, you can create titles, lists or tables just by adjusting the font properties and creating the necessary space among the individual page elements. But this does not provide enough information about the page layout programmatically, even though it could be visually appealing.
Use all elements HTML provides you to distinguish among the layout elements. If it should look like a title, use heading tags. If it should look like a list, code it as a list. If it is a table, make sure that you put your data into a properly tagged table.
This way users can receive more information about the page through assistive technology, and they can also use a different style sheet and still make sense of your site.
This success criterion allows you one way to get out of this requirement, if you provide an equivalent text alternative for formatting. One example for this would be instead of using headings to type out "chapter 1", "chapter 2", etc., together with the chapter titles,but this way you will have to put much more effort into it when it comes to more complex layout elements, for example tables, where you would have to describe the content and the layout of the table. The best way is to stick with headings and table headers in general.
1.3.2: Meaningful Sequence (Level A)
When the sequence in which content is presented affects its meaning, a correct reading sequence can be programmatically determined. (Level A)
There could be a difference between how the page elements appear in the source code and in which order are these elements placed on the screen. In certain cases, the order of layout elements are crucial to obtaining information or to understanding functionality. With CSS techniques, it is possible to place any blocks of information anywhere, so while the original source is not written in an order that makes sense, the actual output can be read properly. However, when the user turns off the style sheets, all of a sudden the original order would appear which is not usable.
In certain cases, the order of data is irrelevant. For example, while a menu visually appears above the main page content, programmatically it can be after the main content, as it does not alter the understanding of the page. But if a document contains tables which are relevant in terms of understanding the flow of information, the tables cannot be inserted into the document later.
1.3.3: Sensory Characteristics (Level A)
Instructions provided for understanding and operating content do not rely solely on sensory characteristics of components such as shape, size, visual location, orientation, or sound. (Level A)
It is very frequent that instructions or information is provided by making use of one or more senses. For example, we hear a sound when a new email arrives, required fields are indicated by a different color, or a user guide refers to the orientation of the screen. This is perfectly acceptable as long as there is more information for those who are not able to use any of their senses.
It is not enough for example to tell the user to click the button on the left, rather, you have to precisely describe which button to press.
When you use sounds to indicate any computer response, also make sure that this information is available by other means, which also do not rely on sensory characteristics. An alternative for a audible warning cannot be indication by a different color for example.