getElementById returns NaN

Question

Consider the following example snippet of my code. I have tried parseInt with no luck. Here, I want javascript to set a number in a cell PICweight then retrieve it later and place it in a different cell totalcabin . You can see here, I want to set the number as 1, but when the code runs, it returns NaN in totalcabin .

<td id="PICweight" type="tel"></td>
<script>
    window.onchange = function setfields() {

        document.getElementById("PICweight").innerHTML = 1;
        var PICweight = document.getElementById("PICweight").value;

        var totalcabin = document.getElementById("totalcabin");
        totalcabin.innerHTML = +PICweight
    }
</script>

Answer 1

There is no value property of td elements. When you use .value on normal html elements (non input elements) you end up with undefined . Later, you use + to implicitly cast undefined to a number, which results in NaN and your subsequent observation.

You should be using .textContent instead of value to get the text inside of the td element.

var PICweight = document.getElementById("PICweight").textContent;