[Steven Zahm]

@ Mitch

Not likely I’ll be adding a setting … I’ll never make everyone happy. This won’t make 0.8, but, I’ll be adding a methods (filters) that will allow these types of changes to be made in an update safe way.

I think this would be the correct pattern for your phone format would be:
((\(\d{3}\) ?)|(\d{3}-))?\d{3}-\d{4}

That would make the entire line like this:

<input type='tel' pattern='((\(\d{3}\) ?)|(\d{3}-))?\d{3}-\d{4}' title='Phone Number (Format: (123) 456-7890)'>

The lines you need to edit are here and here. It’ll change in 0.8. Also, you will not be able to just copy past this, you’ll need to update. I think you’ll see what I mean when you look at the source code.