Support sending bitcoins using webpage URL?
The client Electrum seems to support something like that (using a different method): Aliases:

Aliases may be server names (e.g. ecdsa.org) or email-like addresses (e.g. john.doe@ecdsa.org)
The corresponding Bitcoin address is retrieved by the client, using a descriptor located at a canonical url.
Aliases may be entered in the Electrum client, or used in Bitcoin URIs […]