Test at first something like this :
var reg = /^[\w.+-][COLOR="Red"]+[/COLOR]@[\w.][COLOR="Red"]+[/COLOR][COLOR="Red"]\[/COLOR].com$/i;
With + quantifiers outside the square brackets to allows one or more characters for each class. A back slash is useful to escape the point outside the brackets (I add two points inside the classes but there is other characters to add).
There is many regular expressions (like this according to the RFC 822 grammar for perl) to test email addresses...
For practical use, see this page which give good reasons to take this kind of validation with precautions...
The best test for validation consists to send an email for confirmation !
nb : There is many regular expressions tester on the web (like this one)