Validation in plone

Hi all and one,
How to do server side validation in plone? please help me its very
urgent. i created a validator.py file where i wrote a script for
'special character are not allowed' and calling that script in
movie.py its working fine by validators = ('splcharvalid',), and when
i wrote another script for email validation and want to call in same
field like
validators = ('emailvalid',), and i am calling like this
validators = ('splcharvalid',),('emailvalid',), but its not working
even i wrote like this too
validators = ('splcharvalid','emailvalid',), but its too not
working.. could you please help mr to resolve this problem or may tell
me another way to do validation in plone..