@HihiDanni
1. I only used Hexchat as an example, other clients such as quassel, pidgin, and mibbit should also be able to open such links. For example, I think this link should be parsable to such clients? Your web browser should offer a list of IRC clients registered to handle that URI if you click on links in this form (this one is a dummy example and not real, however)
irc://irc.foobarbaz.net/#frotz
5. Browser-embedded clients such as mibbit or kiwi are good fall-backs if the user only has "default" software, or if they have difficulties configuring their client