Thanks for the info, Chris.  If I have any strokes of genius as time goes on, 
I'll share back w/ the group.  Until then, I'll push a stopgap solution through 
of making a 2o request for the header info.

-----Original Message-----
From: [email protected] [mailto:[email protected]] 
Sent: Tuesday, February 01, 2011 4:19 PM
To: Charlton Galvarino
Cc: [email protected]; [email protected]
Subject: Re: [OpenLayers-Users] getting img request headers

You can't with <img> tags, and you can't ever against remote servers.
It's possible that you could create a layer which requested images only via 
AJAX and get the information that way, but there's no way to do it with the 
normal WMS layers.

-- Chris

On Feb 1, 2011, at 4:01 PM, ext Charlton Galvarino wrote:

> I could make the same request a 2nd time as ajax, but that seems a waste. I 
> just want to snag it as it goes by the 1st time.
> 
> From: Wally Atkins <[email protected]>
> To: Charlton Galvarino
> Cc: Andy Colson <[email protected]>; [email protected] 
> <[email protected]>
> Sent: Tue Feb 01 15:53:50 2011
> Subject: Re: [OpenLayers-Users] getting img request headers
> 
> Interesting ... I don't think that I have ever seen an example where client 
> side javascript can access HTTP response header information on an image. AJAX 
> might be a different story ...
> 
> I'm not saying that it can't be done ... but personally I've not seen it done.
> 
> On Tue, Feb 1, 2011 at 3:33 PM, Charlton Galvarino <[email protected]> 
> wrote:
> Yes, I can see it in firebug, but I want to do it programmatically w/i 
> javascript on my map page.
> 
> A user picks a layer to map; show timestamp below the map.  Another layer; 
> another timestamp.
> 
> -----Original Message-----
> From: Andy Colson [mailto:[email protected]]
> Sent: Tuesday, February 01, 2011 3:32 PM
> To: Charlton Galvarino
> Cc: [email protected]
> Subject: Re: [OpenLayers-Users] getting img request headers
> 
> Firebug?
> 
> On 2/1/2011 2:28 PM, Charlton Galvarino wrote:
> > Hi, all.  Is there a way for me to intercept a normal (single tile) 
> > WMS img request so that I can see the request headers as they come 
> > back?  WMS specs say,
> >
> > =====
> > In order that the Client may determine what value was actually sent, 
> > the server shall label the response object with the actual value 
> > found by rounding. In the HTTP environment, the labeling is 
> > performed using an HTTP response header. For each dimension to which a 
> > rounded-off value was applied, a header line of the following form shall be 
> > sent:
> >
> > Warning: 99 Nearest value used: DIM_NAME=value units
> >
> > where "99" is a defined by HTTP [IETF RFC 2616] for use by 
> > miscellaneous warnings, DIM_NAME is the corresponding request 
> > parameter name, value is the value actually used, and units is the units 
> > attribute (see C.2) for that dimension.
> > =====
> >
> > I want to pull that timestamp out and along to the user to eliminate the 
> > guesswork behind identifying the time the WMS img is trying to represent.
> >
> > I haven't found any real hooks into this, and OpenLayers.Util.onImageLoad 
> > isn't really helping me see the light either.
> >
> > TIA.
> >
> >
> >
> >
> >
> > Charlton Galvarino
> > 1 (803) 233-6205 : voice
> > 1 (803) 223-9579 :   fax
> > [email protected]
> >
> > P.O. Box 50960
> > Columbia, SC 29250
> >
> > _______________________________________________
> > Users mailing list
> > [email protected]
> > http://lists.osgeo.org/mailman/listinfo/openlayers-users
> 
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