function isEmail( email )
{
   var name, address, index_at, index_com, valid;
   valid = 0;

   index_at = email.indexOf( "@" );
   if( index_at < 1 )
      valid = 1;
   else{
      index_at = email.indexOf( "@" );
      name = email.substring( 0, index_at );
      address = email.substring( index_at+1, email.length );
      index_com = address.lastIndexOf( "." );

      if( index_com < 1 )
         valid = 1;
      else{
         if( address.charAt(0) == "[" ){
            if( address.charAt( address.length-1) == "]" )
               address = address.substring( 1, address.length-1 );
            else
               valid = 1;
         }
         if( address.length - (index_com+1) < 1 ||
             address.length - (index_com+1) > 3 )
            valid = 1;
      }
   }

   if( valid == 1 )
      return false;
   else
      return true;
}