[O] Captioning arbitrarily on HTML export?

[David A. Gershman]

Hello,

I have an HTML block:

   #+Caption: Diagram Caption
   #+Label: fig:diacap
   #+begin_html
     <canvas id="mybox" width="200" height="200"></canvas>
      <br>
       <script>
       function drawme() {
          // code to draw on canvas object
       }
       </script>
   #+end_html

and was wondering if there was a way to get an Org Export caption generated?  According to the manual:
   
    "12.9.10  Labels and captions in ODT export
      You can label and caption various category of objects—an inline image, a table, a LATEX fragment
      or a Math formula—using #+LABEL and #+CAPTION lines."

While this is for ODT export, I've seen example online with people putting captions on in-line images:

    #+Caption: A pretty picture
    #+Label: fig:ppic
    [[file:path/to/image.jpg]]

But as you can see, I'm using JS to draw on a canvas and was wondering if OrgExport could generate the captions.  I could always generate the images via some other language and generate the file to do the [[file:path/to/image.jpg]] method, but just thought I'd inquire first.

Thanks!

--dag