data tables

The many benefits of inclusive design and good accessibility

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Digital accessibility is not just about meeting the needs of the disabled or catering to edge cases. Good accessibility impacts everyone5. The benefits of good web accessibility go beyond ADA compliance and risk management. Using effective headings and document structuring can help improve your SEO and search engine placement which benefits your organization and all site visitors. Inclusive design seeks to use digital accessibility techniques to benefit all website visitors.

Specifying headings to structure your page

Making something, like a title, bold doesn’t make it an actual header, that’s a pseudo-heading. The CK-Editor toolbar in Drupal has an option to specify a proper heading (such as H1, H2, or H3). Screen-reader users have an easier time scanning page content that has been divided into headings and sub-headings. Special key commands allow them to jump between headings to scan the page. The Communication Services staff at the College of Arts and Sciences have put together some great video tutorials about using headings to promote good accessibility2. See the References at the bottom of this page.

Specifying alternative text on images, hyperlinks, and links to documents

Specifying alternative text on images helps a screen reader user tell image means and it’s relation to nearby content. Making your online content friendly for screen-readers not only benefits the visually impaired but others who use text-to-speech apps5. In certain contexts, like while driving in a car, people may choose to listen to your content through a text-to-speech app rather than visually read it. Audio narration also helps people follow along with the narrative while they are reading. Many text-to-speech apps highlight what is being read.

Alternative text should also be added to hyperlinks. To add alt text to a link with CK-Editor click the ‘Advanced’ tab and add your alternative text under ‘Advisory Tile’ (becomes both a hover tool-tip and alt text for the link). It’s a good idea to include the word ‘website’ in your links to external sites to inform readers that they are going to a new site. Relative links are used to build internal links between pages.  For example a path might look like: ‘/folder/sub-folder/name-of-page.html’. Absolute links send readers out to external sites. A URL path might look like: ‘http://www.someplace.com/folder/sub-folder/name-of-page.html’.

Instead of just linking to untagged PDF files it’s recommended to create webpages with the same content as the file then place a link to the PDF, if needed. This is because PDF files are generally not as accessible as HTML pages4. It takes more effort to make a PDF file more accessible than an HTML page. Many universities and schools of pharmacy are already creating student manual documents in HTML format. Some post important current student information in both HTML and PDF format. The ‘ASC CE Training Links to Files’ training video4 says its’ imperative that you indicate the file type in the link text such as including ‘[pdf]’ in brackets.

Making data tables accessible

It’s important for tables to be made accessible as possible to those using screen readers. The most common issue for Word documents with data tables in them is missing table row headers <th> (usually in the first row).

To add a header row in MS Word 2013:
– Right-click on the table and choose ‘Table Properties’.
– Under the ‘Row’ tab check ‘Repeat as header row’ at the top of each page.

You will be able to see the <th> in the table structure in Acrobat Pro’s ‘Tags’ panel after you’ve exported to PDF. Missing table row headers can also be added in Drupal’s CK-Editor or another HTML editor app, like Dreamweaver or Kompzer.

References

1) ASC Communication Services. ASC CE Training – Accessibility. The Ohio State University College of Arts and Sciences. 2015.
2) ASC Communication Services. ASC CE Training Headers and Accessibility.  The Ohio State University College of Arts and Sciences. 2015.
3) ASC Communication Services. ASC CE Training – Alternative Text.  The Ohio State University College of Arts and Sciences. 2015.
4) ASC Communication Services. ASC CE Training Links to Files. The Ohio State University College of Arts and Sciences. 2015.
5) Paul Boag. Accessibility is not what you think. Boagworld. 2014.
6) Accessibility at Penn State [Internet]. Tables for Data in HTML. Pennsylvania State University, University Park, PA. [cited 13 Feb 2016]

Using HTML tables in the correct way

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Using HTML tables in the correct way will help make your sites more accessible to all viewers and user agents. Using tables for layout of webpages was a popular technique starting in the late 90s that had fell out of favor by 2006-2007 with the rise of web standards movement. Tables primary purpose is to display tabular data. If you are using tables of layout with empty cells, missing table headers <th>, or fixed widths you are using them in an incorrect way that introduces accessibility problems into your web site.

The preferred method late 2000s method for laying out pages was to wrap content in <divs> and use CSS (cascading style sheets) to place the <div> areas in columns or grids. HTML 5 introduced additional structural elements in HTML such as <article>, <nav>, and <aside> that could also be used with CSS layout techniques. A big problem with layout tables used in the late 90s was that they mixed presentational data in with content. CSS was created so the presentational markup could be separated from the ‘semantic’ HTML content. That way the same content could be more easily styled in a variety of ways by switching out style-sheets. It would be much more difficult to change the appearance of layout tables with inline fixed widths and other deprecated presentational markup that shouldn’t be in HTML.

Some key features of accessible tabular data tables as I understand them, are:

– They have a <caption> tag included at the top of the table. These can be hidden visually but be seen by screen readers or other tools that read text.
– They have header cells, <th>, which help to label table columns or rows (depending on how the table is laid out). Site visitors using screen readers can jump between these headings.
– They have a <thead> tag that’s used to wrap the header cells, <th>.
– They have the have the same number of columns in every row and same number of rows in every column. Fancier layouts with cells spanning multiple columns can yield accessibility errors in validators and navigational problems in screen readers.
– They are basic and straightforward in their layout. Nested tables within tables or cells spanning multiple rows will confuse  accessibility validators and screen readers.

I’ll update this post as I learn more about best practices for using data tables in HTML. I’ll also share more insights in theming HTML 5 content as I discover new techniques.