Otto Otto - 1 month ago 4x
HTML Question

JS RegEx to match certain patterns only

I need to adapt my Javascript RegEx to match certain patterns only. The RegEx is used in the html5

attribute to validate an input field.

I want to accept alphanumeric pattern of the following types only:

A-AAAA or BB-BBB (the intended pattern is: 1 digit before the "-", and 4 digits after the "-", or 2 digits before the "-", and 3 digits after the "-").

My current RegEx is:


This one works, but accepts CC-CCCC as well, which is obviously a valid input pattern, but not the intended pattern. It accepts DDD-DDDD as well; valid again, but not intended.

Could you please assist adapting the pattern?


You can use alternation:


RegEx Demo