function checkmailsyntax(emailaddress) {

   var valid_eaddress = true;
   var filter  = /^([a-zA-Z0-9_\.\-\'])+\@(([a-zA-Z0-9\-])+\.)+([a-zA-Z0-9]{2,4})+$/;
   if (!filter.test(emailaddress))
   {
       valid_eaddress = false;	
       return valid_eaddress;	
   }
   else
   {
       valid_eaddress = true;
       return valid_eaddress;
    }
}