	<!--
function ClearForm(form){
   form.age.value = "";
   form.hrmax.value = "";
   form.thr60.value = "";
   form.thr15.value = "";
}

function hrMax(age) {
   maxHR=(220 - age);
   return maxHR;
}

function thrMin60(age) {
   minTHR60=Math.round((220 - age)*0.6);
   return minTHR60;
}

function thrMin15(age) {
   minTHR15=Math.round(((220 - age)*0.6) / 4);
   return minTHR15;
}

function thrMax60(age) {
   maxTHR60=Math.round((220 - age)*0.8);
   return maxTHR60;
}

function thrMax15(age) {
   maxTHR15=Math.round(((220 - age)*0.8) / 4);
   return maxTHR15;
}

function checkform(form) {
   if (form.age.value==null||form.age.value.length==0) {
      alert("\nPlease complete the form first");
      return false;
   }

   else if (parseFloat(form.age.value) <= 0||parseFloat(form.age.value) >121) {
           alert("\No way.  The oldest known living human is 121 \nPlease enter your age again.");
           ClearForm(form);
           return false;
        }
   return true;
}

function computeform(form) {
   if (checkform(form)) {
      form.hrmax.value=hrMax(form.age.value);
      form.thr60.value=(thrMin60(form.age.value)) + " - " + (thrMax60(form.age.value));
      form.thr15.value=(thrMin15(form.age.value)) + " - " + (thrMax15(form.age.value));
   }
   return;
   
   	//-->
}