There is the idea of a Universal Dialog Window for application. HTML-standard should define the Dialog Window API for browsers and JSON-object for the browser's Dialog Window API. See article on this topic (see URL).
Sincerely, Klinachev Nikolay Vasilevich
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Status: Additional Information Needed
Change Description: none yet
It's difficult to assess from just the description.
If you wish to pursue this, we invite you (or others) to follow the steps outlined in: http://www.w3.org/html/wg/wiki/ExtensionHowTo