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//Written by Manuel Villanueva

function IVrate(form) {
if (form.charge[0].checked) {
   
//calculate time as hours
var answer = form.volume.value / form.time.value;
}

//calculate time in minutes
else {
var answer = form.volume.value / (form.time.value / 60);
}
form.answer.value = Math.round(10*answer)/10;

//alert
if((form.time.value==null)||(form.time.value=="")||(isNaN(form.time.value))){
alert('Please enter time with numbers only');
form.time.focus();
form.time.select();
return false
}

//alert
if((form.volume.value==null)||(form.volume.value=="")||(isNaN(form.volume.value))){
alert('Please enter volume with numbers only. Use a period for decimal place.');
form.volume.focus();
form.volume.select();
return false
}
}
// end hiding -->