[Seaside] Usage of WAIframeTag

[Martin J. Laubach]

| (html context actionUrl withParameter: (canvas callbacks
|  registerActionCallback: [
|  		self session returnResponse: (WAResponse
|  			document: ...
|  			mimeType: ...
|  			fileName: ....) ]))

  Great this works nicely, thank you very much.

  Would it be a problem to cache the result from (html context actionUrl...)
in a Dictionary in my session so that a given document will always give
out the same URL so the browser will cache it?

	mjl