Notes on Accessibility

Megan's picture

She has: 11,421 posts

Joined: Jun 1999

I attended a really good accessibility seminar this afternoon and I thought I'd share some of my notes with you. I'm sure a lot of this will be old hat to those who really study accessibility, but much of it was new to me so I thought I'd share.

First of all, to answer a question that came up awhile back, alt tags for visual interface graphics should be empty (alt="") - no space, nothing. If you leave out the alt tag a screen reader will just read the file name of the graphic! So there's another reason not to leave them out.

Secondly, it's really important to provide a way to skip over navigation. The way most pages are structured is logo first, then navigation, then content. A screen reader will just start reading the page from the start, which means that they have to listen to all the navigation elements. So, what was suggested is to put a 1x1 px transparent gif right after the logo which links to a target at the start of the actual content. The alt text would read something like "skip navigation" or similar.

Oh, and screen readers actually read punctuation, so if you have a [ it will say "bracket".

Other bits: don't put important text in images if at all possible, use longdesc to provide more information about images, some also use a little "D" beside the image to link to a longer description (since longdesc isn't always supported). There was lots about forms ( tag beging most interesting); also other tags and attribures like and "optgroup" for . For tables the "scope" attribute for th was new to me, also "header" attribute for td's. Good stuff.

Suzanne's picture

She has: 5,507 posts

Joined: Feb 2000

http://diveintoaccessibility.org/
http://secrets.synapticimpulse.com/index.php?code=rcsubway (sample accessible and valid forms)

For some real life pages to poke around in. Smiling

Joe Clark has some big time reading on Accessibility as well (and writing -- he wrote a book on the topic), but it can be heavy reading. If anyone is interested, I'll post the ./ interview with Joe Clark as well as the url for his book.

Mark Pilgrim (who wrote Dive Into Accessibility) edited Joe Clark's book.

Thanks for the topic, Megan!

disaster-master's picture

She has: 2,154 posts

Joined: May 2001

Hi Meg,

Yes, great topic!! I wasn't aware of that bit about the alt tag for the nav. Thanks. Smiling

I would like to hear more if you have time to post some things. Suzanne gave some great links as well. I have spent a lot of time at dive into accessibility.

Will check back for class #2. Laughing out loud

Busy's picture

He has: 6,151 posts

Joined: May 2001

label and fieldset isn;t fully supported but is good to use them, also summary for tables (acts like a alt tag for the screen reader).
There are a few types of screen readers, some that can read or adentify html and javascript and others that can't understand any html so would display yor page as if tables, css etc were turned off.

when a screen reader reads a table it starts top left and worls right until the read of the row then down one

1 | 2 |
3 | 4 |
  5
6 | 7 |

so if you wrote the text to go downwards (1,3,5,6 - 2, 4,7 ) it wont get read that way, would be read - 1,2,3,4,5,6,7 so people using screen readers have a real tough time sometimes trying to make it understandable. links are another issue, links for screen readers should have a note or image displaying its an outside link.

Megan's picture

She has: 11,421 posts

Joined: Jun 1999

That's what those scope and header and attributes do for tables - help them know what header goes with what. Even if things aren't 100% supported it may be a good idea to start implementing them.

Oh, and this is another big argument in favour of proper coding, and against frames and pop-ups unless necessary and especially appropriate.

My notes are at work so I can't really add much now.

Busy's picture

He has: 6,151 posts

Joined: May 2001

http://aprompt.snow.utoronto.ca/overview.htm is a handy little accessibility checker

and here is a site on disability statistics http://dsc.ucsf.edu/UCSF/ (US stats but still helpful for non US people)

taff's picture

They have: 956 posts

Joined: Jun 2001

ooh! Thanks for this thread. Searching is a good thing Smiling

I'm on an accessibility crash course right now for an upcoming project so any other nuggest of wisdom would be appreciated. Actually the criteria is "should adhere to Section 508 Guidelines". From what I've been reading so far, Section 508 is either less stringent or more vague than other sandards such as W3C - I just can't determine which.

Watchfire seems to have a pretty good online scanning tools although it only does a page at a time:

http://webxact.watchfire.com/scanform.aspx

.....

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