输出文本框显示“Infinity”

Question

以下是函数中的计算公式。目前我在计算结果上遇到麻烦，一些输出在文本框中显示“Infinity”。

需要帮助。

function Calc() {
  let arr = document.getElementsByName('qty');
  let tot = 0;

  for (let i = 0; i < arr.length; i++) {

    let radios = document.getElementsByName("group" + (i + 1));

    for (let j = 0; j < radios.length; j++) {
      let radio = radios[j];

      if (radio.value == "Yes" && radio.checked) {
        tot += parseInt(arr[i].value);
      }

    }

  }

  document.getElementById('total').value = tot;
  var stdHour = ((tot * 1.15) / 3600);
  document.getElementById('stdHour').value = stdHour.toFixed(4);
  var earnHour = ((tot * 1.15) / 3600) *     document.getElementById('unitNum').value;
  document.getElementById('earnHour').value = earnHour.toFixed(3);
  var headC = ((earnHour / 19.8) / document.getElementById('numDays').value) || 0.00;
  document.getElementById('hc').value = headC.toFixed(3);
  var earnDays = ((document.getElementById('unitNum').value / ((document.getElementById('numHeadC').value / stdHour) * 5.27)) / 3) || 0.00;
  document.getElementById('days').value = earnDays.toFixed(3);
  document.getElementById('perday').value = ((document.getElementById('numHeadC').value / stdHour * 5.27) * 3).toFixed(0);
  document.getElementById('hcperday').value = ((document.getElementById('output').value / 19.8) * stdHour).toFixed(3);
}