function CalorieCounter_Update(type, val)
{
 var minutes_obj = document.getElementById ('caloriecounter_minutes');
 var exercise_obj = document.getElementById ('caloriecounter_exercise');
 var food_obj = document.getElementById ('caloriecounter_food');

 var exercise_val = exercise_obj.options[exercise_obj.selectedIndex].value; // CaloriesPerMinute
 var food_val = food_obj.options[food_obj.selectedIndex].value; // CalorieConsumption
 var minutes_val = food_val / exercise_val;

 minutes_obj.value = Math.round (minutes_val);
}