Validate an email
How to check an email address is valid and exist on internet?
to check if the address is valid, use regular expressions. that's relatively easy and there are a lot of examples on the net. to check if the address is genuine, you'd have to communicate with the remote mail server and check its output. this takes time and isn't that easy. there are ready to use snippets for that on the net, too. but again: this check may take up to some minutes. better send a validation email and let the user proceed after validating.