var re = /^(([^<>()[\]\\.,;:\s@\"]+(\.[^<>()[\]\\.,;:\s@\"]+)*)|(\".+\"))@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\])|(([a-zA-Z\-0-9]+\.)+[a-zA-Z]{2,}))$/; // format of an email. ex. blah@blue.com function testEmail( field ) { var email = field.value.toLowerCase(); field.value = email; var ok = re.exec(email); if( !ok ) { window.alert("\"" + email + "\" is not a valid email address. Please re-enter."); return false; } else { return true; } }