How to specify a general note for screen readers in html

Question

I have a HTML5 page with a lot of SVG-rendered math expressions. For each one of those math snippets, you can click to view a new tab/page with the math expressed in MathML (there's a link surrounding each SVG math snippet).

I could put a title= attribute on the link to tell screen-readers what the link is for, but it is really annoying to hear that for every bit of math when there's a lot on the page or in a sentence.

My question is twofold:

1. Is it possible to put a general note on the page so that screen-readers know about the alternative math representation?
2. If it is possible, is that a good solution?

Here is a skeleton mock-up of the current situation. Imagine this in a web app that does not support MathML so the math is rendered as SVG. Each companion htm file contains the MathML and LaTeX representations of the math in a plain html file (not part of the web app).

<some equation in SVG/>
where 

<a href="eq1.htm"><svg aria-labelledby="eq1">
  <desc id="eq1">x sub i. 
   Click image for alternative format. 
   Opens in new window or tab</desc>
</svg></a>
is the etc ...
<a href="eq2.htm"><svg aria-labelledby="eq2">
  <desc id="eq2">y sub j. 
   Click image for alternative format. 
   Opens in new window or tab</desc>
</svg></a>
is the etc ...
and
<a href="eq3.htm"<svg aria-labelledby="eq3">
  <desc id="eq3">R sub i j. 
   Click image for alternative format. 
   Opens in new window or tab</desc>
</svg></a>
is the ... etc etc

Listening to that note for each bit of math gets old (Click image for ... etc). So my thought was that putting something like this at the top of the page would be more useful:

<unknown> <!-- tag at the top of the page -->
For alternative representation of any math on this page, click the image.
Opens in new window or tab.
</unknown>

and then each math SVG text description would contain the math description only, without the note about alternative representations.

Answer 1

look at MathML specification, it's now compatible with recent screenreader.

links:

• http://www.quantumrlv.com.au/news/jaws-16-has-arrived/
• http://www.w3.org/Math/

Answer 2

You can add the general note to your page above the Math, so long as it is not in any form, then the screen reader should read it, and if it help to clarify things then it should be helpful.

it is really going to depend on your users and on what screen readers (version) they are using.

if they are power users then the note above is likely a good idea however if this is for the general public then it may not work.