[uf-discuss] Tutorial on AHAH (such a cool technology!)

Sun Mar 4 00:45:45 PST 2007

> Costello, Roger L. wrote: Hi Folks,
> 
> I have created a tutorial on AHAH (Asynchronous HTML and
> HTTP)
> 
> http://www.xfront.com/microformats/AHAH.html
> 
> Comments welcome.

Printable version please! Ane that doesn't take 12 pages to print...  (He
also grumbles about lack of back button in presentation but glad the
presentation was not 96 pages...)

> The purpose of AHAH is to enable an HTML document to
> dynamically fetch HTML from other documents, thus    
> creating one document that is an assembly of information
> from many HTML documents.

I assume you got AHAH from the efforts documented here[1]? 

> Provide a placeholder in your HTML document where you
> want the fetched HTML data to be inserted.  Identify that
> placeholder using the id attribute, e.g.,</li>

Shades of ASP.NET!  Now we've got client-side "placeholders" too! ;-P

> The target HTML document (the HTML that you are fetching)
> must not be a whole HTML document; it must just be an HTML 
> fragment.

How does that work with content types?  If it is a fragment then it is not a
valid text/html, right?  Is there a content type of "HTML Fragment?"  If
not, shouldn't there be and it be used instead of what you are using?
Alternately, shouldn't you include the full HTML <head> and <body> trimmings
but then extract the innerText from <body> before inserting?  I think this
is actually something that could potentially even be discussed by W3C TAG
for a finding on best practices (i.e. inclusion of HTML fragments.)

Lastly, <a
href="javascript:ahah('Waldorf-Astoria-Photo.html','Photo');">photo</a>
hides the content from search engines, which is not good.

Christian Heilmann wrote:
> This example does that (except for the templating part):
> http://beginningjavascript.com/Chapter8/exampleXHR.html

This approach is definitely better because it lets the search engines see
the link:

	<a href="perfect_day.txt" onclick="return
simplexhr.doxhr('txtcontainer1',this.href)">Perfect Day</a>

Another alternative that seems cleaner to me would be to code it like this
and let your ahah.js annotate the link for you:

	<a href="Waldorf-Astoria-Photo.html" rel="ahah">photo</a> 

Oh course this last suggestion will probably run me afoul of the microformat
police since rel="ahah" hasn't even been officially proposed yet and I
didn't bring it up on [uf-new]... ;-P

-- 
-Mike Schinkel
http://www.mikeschinkel.com/blogs/
http://www.welldesignedurls.org
http://atlanta-web.org - http://t.oolicio.us
"It never ceases to amaze how many people will proactively debate away
attempts to improve the web..."

[1] http://en.wikipedia.org/wiki/AHAH