Exactly
I'm not sure if there are protocols with other chars then a-z in it, but it supports at least http, https, ftp etc. And if you ever see another protocol, you can always change it
Btw:
"/^[a-z]+:\/\//i"
The "main preg" is between / and /
The ^ stands for "begins with";
[a-z]+ is one of more letters
: is a colon
\/ is a /, but should be escaped with a \
\/ is another one
/ is the last / of the preg
i means case insensitive
/ –
