var str_wrong_adults_number = 'There should be at least one adult-passenger\n' ;

function check_passengers_number( form )
{
	var adults_field = form.adults_number ;
	var adults_number = get_selected_value( adults_field ) ;	
	
	var r = ( adults_number != 0 ) ;
	
	if ( !r )
	{
		adults_field.focus() ;
		alert( str_wrong_adults_number ) ;
	}
	
	return r ;
}