Follow up r75627 (code review comments):

Follow up r75627 (code review comments):
* Replace background coloring with a label insertion on the right or left of input depending on language direction.
* User side validation of email according to an HTML5 specifications provided by Simetrical :
http://www.whatwg.org/specs/web-apps/current-work/multipage/states-of-the-type-attribute.html#e-mail-state
 Code comments should be self explaining.

Possible follows up:
- use JQuery Validation plugin
- make the validation part a mediawiki validation module
- server side validation