Question

what I need is not email validation..
Its simple.
Allow @hello.world or @hello_world or @helloworld but @helloworld. should be taken as @helloworld so as @helloworld?

In short check for alphabet or number after . and _ if not than take the string before it.

My existing RegEx is /@.([A-Za-z0-9_]+)(?=\?|\,|\;|\s|\Z)/ it only cares with @helloworld and not the @hello.world or @hello_world.

Update:

So now I got a regex which deals with problem number 1. i.e. Allow @hello.world or @hello_world or @helloworld but still What about @helloworld. should be taken as @helloworld so as @helloworld?

New RegEx: /@([A-Za-z0-9+_.-]+)/

Answer 1

Don’t use a regex for that.

Use…

$valid = filter_var($str, FILTER_VALIDATE_EMAIL);