If you'd like to validate the email address, there are some good implementations of regular expressions to do this available if you look for them. Your regular expression is not adequate to the task.

Assuming this is a CGI script (from the <br> tag), then simply printing an HTML fragment is also inadequate. You need to emt a complete HTML document. If you look around, you should find many examples of good CGI code, starting with using the CGI module itself.