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HEASARC Efforts for Section 508 Compliance

  • Pages in other languages: This is OK, as long as there's a summary paragraph (or at least a phrase) in English explaining the purpose of the page (as for a page about how to deal with BWI airport, in Japanese for Japanese visiting scientist consumption), or an English equivalent of the page (for a Japanese page describing work done on Astro-E2, which might be useful for English readers as well).

The most common section 508 problems with our pages

Below are listed some of the most common problems and their solutions. In order to claim your site is compliant, you need to make sure it passes ALL the rules.

Alt Tags

There is a government effort to make web pages accessible by all, including those with disabilities such as blindness. To that end, we are trying to comply with the Section 508 rules (see Web Accessibiliy Made Easy) and become accessible at the Priority 1 level (at least). In a nutshell (and at a minimum), this means adding alt tags to images and image map hotspots, and giving each FRAME tag a title.

I have already done this to the headers on the HEASARC and EUD. If you have images on your pages, please take the time to add some brief descriptive text to your images.

EXAMPLES

<img alt="image" src="image.gif">
This isn't very useful since it doesn't give a blind person equal access to the information imparted by the image. Better would be:
<img alt="artist concept of the Chandra satellite in space" src="image.gif">

<img alt="*" src="/Images/gold_ball.gif">
Use of the asterisk alt tag is appropriate for bulleted lists that use images instead of <LI>. Be careful: if you use different color bullets to denote different things, make the alt tag different as well.

<img alt="" width=1 height=1 src="/Images/pixel.gif">
This is often used as a spacer. The blank alt tag is understood as such.

LONGER DESCRIPTIONS

If you feel the desire to describe a graph or chart in great detail, you should use a longdesc tag (note that there's *also* an alt tag):

<img alt="chart showing HEASARC Web access versus time" longdesc="chart_longdesc.html" src="chart.gif">

where chart_longdesc.html is an HTML file with plain text describing in detail what the chart looks like (x and y axes, shape of the curve, etc.) I've recently learned that this is not well supported and that a link (denoted with the letter "D") near the image that links to the longdesc.html will help many who use older assistive software.

IMAGEMAPS

If you have an image map with <area shape=...> tags, put an alt tag there defining where the link goes.
E.g. <area alt="HEASARC Home Page" shape="rect" coords...>.

Frames

Each FRAME should have a title.
E.g. < Title="Content" src="blah.html" name="content_frame">
< Title="Menu" src="blah_menu.html" name="menu_frame">.

Who This Applies To

If your page has an <img> or <area> imagemap hot spot, you should check to make sure each has an alt tag. Don't forget the little stuff: logos, icons, graphical headers, graphical bullets, horizontal bars, images, graphs, and buttons.

Checking for Compliance

If you want to know if your page is compliant, go to Bobby and run the Bobby checker (make sure you select the section 508 radio button).

Other considerations

NASA Policies

A web page outlining NASA policies is available.

More 508 requirements

Web browsers for the blind read all the links preferentially. Try to make your links meaningful on their own. Links like click here are not very useful to those users, or to sighted users who skim pages by reading the links.

The web browsers for the blind also read pages in order. If you're sighted, you can determine with a glance that the navigation bars on this page are at the top and left, and you can very quickly determine where the real content lives. Screen readers don't have that ability. They will read this page in order of table cells: left to right and top to bottom. Blind users will hear every link (NASA logo, the seven across the top and the many down the left side) before any content is read. To alleviate this painful process, I have added an invisible link (you can find it at the top of the page a few dozen pixels above the NASA logo) which takes the user to the page content. If you're using the standard headers, this is taken care of for you. If you're developing new sites, keep this in mind and allow your visually-impaired users to skip the navigation and go straight to the content.

Try not to convey information solely by color-coding. You can now check what your pages look like to the color-blind.

Page author: Karen Smale
Last updated: Monday, 21-Apr-2025 17:48:34 EDT.