I am trying to find/write a regex that does not allow the email address to end in .mil when input into a form.

This is what I have to allow ONLY emails ending in .mil, but in this instance I would like the opposite. My understanding of RegEx is amateur at best:

^[_a-zA-Z0-9-] (\.[_a-zA-Z0-9-] )*@[a-zA-Z0-9-] (\.[a-zA-Z0-9-] )*(\.mil)$

Thanks! If you're willing, a break down of the different pieces or the change would be very helpful so I understand better moving forward.

CodePudding user response：

Use a negative lookbehind at the end.

^[_a-zA-Z0-9-] (\.[_a-zA-Z0-9-] )*@[a-zA-Z0-9-] (\.[a-zA-Z0-9-] )*(?<!\.mil)$