I got a Regex that validates my mail-addresses like this:
([a-zA-Z0-9_\\-\\.]+)@((\\[[0-9]{1,3}\\.[0-9]{1,3}\\.[0-9]{1,3}\\.)|(([a-zA-Z0-9\\-]+\\.)+))([a-zA-Z]
Old post - needed the same RegEx. The accepted answer did not work for me, however, this did.
^(|([a-zA-Z0-9_\-\.]+)@([a-zA-Z0-9_\-\.]+)\.([a-zA-Z]{2,5}){1,25})+([;.](([a-zA-Z0-9_\-\.]+)@([a-zA-Z0-9_\-\.]+)\.([a-zA-Z]{2,5}){1,25})+)*$
Retrieved from this post, however, the accepted answer did not work either, but the Regex on the link WITHIN the post did.
abc@abc.com - validates
abc@abc.com;123@qwer.com - validates
abc@abc.com; - does not validate
empty string - validates
If you want to validate against an empty string, then remove the | at the beginning of the regex