How can I setup a custom field validation and have if so that it can be
blank, OR match my regular expressionCurrently I have: (?#YYYY-MM-DD HH:mm:ss)[1]\d{3}-\d{2}-\d{2}
\d{2}:\d{2}:\d{2}$Really what I guess what I think I’m looking for is
/([2]\d{3}-\d{2}-\d{2} \d{2}:\d{2}:\d{2}$|^$)/
How can I setup a custom field validation and have if so that it can be blank, OR match my regular expression Currently I have: (?#YYYY-MM-DD HH:mm:ss)^[12]\d{3}-\d{2}-\d{2} \d{2}:\d{2}:\d{2}$ Really what I guess what I think I'm looking for is /(^[12]\d{3}-\d{2}-\d{2} \d{2}:\d{2}:\d{2}$|^$)/
perldoc perlre will tell you more than you ever wanted to know, but
something like:
/^(?:foo|)$/ or /^foo$|^$/
is what you want to emulate.
Remember that the (?#YYYY-MM…) part needs to be self contained since
it isn’t an active part of the regex.
-kevin