function handleData(f)

{

     var errormsg = "";	

     var msg = "";

     var in_age = 0;

     var in_resting_heart_rate = 0;		

     var predicted_max_heart_rate = 0;

     var heart_rate_reserve = 0;

     var beats_per_minute_60 = 0;

     var beats_per_ten_second_count_60 = 0;

     var beats_per_minute_80 = 0;

     var beats_per_ten_second_count_80 = 0;



     for (var i = 0; i < f.length; i++)

     {

	  var d = f.elements[i];

	  // field must be numeric

	  if (d.name == "age")

	  { 

	      if (!numericCheck(d.value)) 

	      {

	          errormsg += d.name + " must be numeric!\n";

	          d.focus();

	          alert(errormsg);

	          return false;

	      }

              else

	      {	

		  in_age = parseInt(d.value);

	      }

  	  }

	  else 

	  // field must be numeric

	  if (d.name == "resting_heart_rate")

	  { 

	      if (!numericCheck(d.value)) 

	      {

	          errormsg += d.name + " must be numeric!\n";

	          d.focus();

	          alert(errormsg);

	          return false;

	      }

              else

	      {

		  in_resting_heart_rate = parseInt(d.value);

	      }	

  	  }

     }	

	  

     predicted_max_heart_rate = (220 - in_age);

     heart_rate_reserve =

	(predicted_max_heart_rate - in_resting_heart_rate);

     beats_per_minute_60 = 

	((heart_rate_reserve * .60) + in_resting_heart_rate);

     beats_per_ten_second_count_60 = (beats_per_minute_60 / 6);

     beats_per_minute_80 = 

   	((heart_rate_reserve * .80) + in_resting_heart_rate);

     beats_per_ten_second_count_80 = (beats_per_minute_80 / 6);

     

     msg += "----------------------------------------------------\n";

     msg += "Your Heart Rate Calculations are : \n"; 

     msg += "----------------------------------------------------\n"; 

     msg += "Predicted maximum heart rate : " + predicted_max_heart_rate + "\n"; 

     msg += "Heart rate reserve : " + heart_rate_reserve + "\n"; 

     msg += "Beats per minute for 60% level : " + beats_per_minute_60 + "\n"; 

     msg += "Beats at 10 second count 60 % : " + beats_per_ten_second_count_60 + "\n"; 

     msg += "Beats per minute for 80% level : " + beats_per_minute_80 + "\n";  

     msg += "Beats at 10 second count 80 % : " + beats_per_ten_second_count_80 + "\n";	  

     //alert(msg);

     document.myform.maxrate.value = Math.round(predicted_max_heart_rate);

     document.myform.bpm60.value = Math.round(beats_per_minute_60);

     document.myform.bpm10s60.value = Math.round(beats_per_ten_second_count_60);

     document.myform.bpm80.value = Math.round(beats_per_minute_80);

     document.myform.bpm10s80.value = Math.round(beats_per_ten_second_count_80);

     return true;

}

	

//  check numeric function

//  return false if not numeric

function numericCheck(num) 

{ 

    var v = parseInt(num);	

    if (isNaN(v) || (v < 1) || (v > 999))

    {	

	return false;

    }

    else

    {	

	return true;

    }	

}