Question

I’m trying to write a regular expression, for use in a javascript function, to test datetimes.

I’m wanting to allow dates in the following formats only:

YYYY-MM-DD HH:mm:ss
YYYY-MM-DDTHH:mm:ss
YYYY-MM-DD HH:mm
YYYY-MM-DDTHH:mm

This is as far as I’ve managed to get so far:

/^(19[0-9]{2}|2[0-9]{3})-(0[1-9]|1[012])-([123]0|[012][1-9]|31)[ \/T\/t]([01][0-9]|2[0-3]):([0-5][0-9]):([0-5][0-9])$/

It does what I want except requires hours, minutes and seconds rather than hours and minutes with seconds optional.

Thanks for your help!

I’ve written a small jsFiddle with some test data to make your lives easier. Just update the pattern variable and run it and the table should match up.

http://jsfiddle.net/smMJC/

Answer 1

UPDATE: I updated this answer to change (…) to (?:…) so your capturing won’t be messed up.

Try this:

/^(19[0-9]{2}|2[0-9]{3})-(0[1-9]|1[012])-([123]0|[012][1-9]|31)[ \/T\/t]([01][0-9]|2[0-3]):([0-5][0-9])(?::([0-5][0-9]))?$/

Updated fiddle:
http://jsfiddle.net/smMJC/5/

What I did was changing

:([0-5][0-9])

to:

(?::([0-5][0-9]))?

which means making that part optional. (The double colon is intentional because it is a (?: ... )? non capturing group outside and a literal “:” inside.

Also, you may want to change:

[ \/T\/t]

to:

[ Tt]

unless you really want to match strings like:

2013-01-01/15:30:30

with a slash instead of T – compare those two demos:

• http://jsfiddle.net/smMJC/3/
• http://jsfiddle.net/smMJC/4/