Text input elements returning 'undefined' to .csv file - node.js

Question

EDIT: I figured the problem out. It had turned out I was appending the items to themselves. The correct method I worked out would be to make a new variable as such:
var form = document.getElementById("listItems");
and then editing the document.body.appendChild(itemName); to
form.appendChild(itemName) and form.appendChild(itemQuantity) respectively.
For context, the call to the backend looked as such:
<form action="/buy" method=post id="listItems">
<input type="submit" value="Send">
</form>
When creating text boxes, I save the contents to a .csv file, however when I access these files I am returned a value of 'undefined'.
I looked into the code, and found that the input is saving itself as undefined no matter what was put in the text box.
Specifically these text boxes,
<script>
function addItems(){
var itemName = document.createElement("input");
itemName.setAttribute('type', 'text');
itemName.placeholder = "itemName";
document.body.appendChild(itemName);
var itemQuantity = document.createElement("input");
itemQuantity.setAttribute('type', 'text');
itemQuantity.placeholder = "itemQuantity";
document.body.appendChild(itemQuantity);
}
</script>
var itemName and itemQuantity show up in console.log and in the file as undefined values.
What should've happened was that when I ran:
var itemN = req.body.itemName;
var itemQ = req.body.itemQuantity;
await fs.appendFile('receipt.csv', "\n" + itemN + " " + itemQ, err => {
if (err) {
console.error(err);
}
console.log(itemN, itemQ);
// done!
})
It should have appended to the file 'receipt.csv' as ItemN + ItemQ as a string, however when accessed the file shows the submitted text as: Undefined Undefined.