regex - Regexp to grab protocol from URL -

let's have variable called url , it's assigned value of http://www.google.com. can received url via ftp, hence it'll ftp://ftp.google.com. how can have grab before :? i'll have if/else condition afterwards test logic.

/^[^:]+/   

if want prevent 'www.foobar.com' (which has no protocol specified) match protocol:

/^[^:]+(?=:\/\/)/