<!--
function btncalczoneA()  
{ 
var error = false; 
if (document.forms['thr'].txtageA.value == '0' || document.forms['thr'].txtageA.value == '') {
	alert('Please enter a number greater than 0 for Age.');
	document.forms['thr'].txtageA.focus();
	error = true;
	return false;
}
if (document.forms['thr'].rhr.value == '0' || document.forms['thr'].rhr.value == '') {
	alert('Please enter a number greater than 0 for Resting Heart Rate.');
	document.forms['thr'].rhr.focus();
	error = true;
	return false;
}

if (error == false) {
	ageA = document.forms['thr'].txtageA.value;
	var rhr = eval(document.forms['thr'].rhr.value);

	maxrateA = 220 - ageA;

	minzoneA = ((maxrateA - rhr)*(.55)) + rhr;
	document.forms['thr'].minA.value = parseInt(minzoneA);

	maxzoneA = ((maxrateA - rhr)*(.85))+ rhr;
	document.forms['thr'].maxA.value = parseInt(maxzoneA);

	return true;
}
}

function btncalczone()  
{ 
if (document.forms[0].txtage.value == '0' || document.forms[0].txtage.value == '') {
	alert('Invalid data.  Please check and re-enter!');
	return false;
}
else
{
	age = document.forms[0].txtage.value;

	maxrate = 220 - age;

	minzone = (maxrate)*(.55);
	document.forms[0].txtminzone.value = parseInt(minzone);

	maxzone = (maxrate)*(.85);
	document.forms[0].txtmaxzone.value = parseInt(maxzone);

	return true;
}
}

-->