function checkContact(form) {
 if (!checkinput('naam','Please fill in your name',form,type='string') ) {return false} ;
 if (!checkinput('email','Please fill in a correct email address',form,type='email') ) {return false} ;
 if (!checkinput('website','Please fill in your website address',form,type='string') ) {return false} ;
 if (!checkinput('telefoon','Please fill in your phone number',form,type='string') ) {return false} ;
 return true;
}