valor do getElementById
document.getElementById('numbers').value
GutoTrosla
document.getElementById('numbers').value
document.getElementById("fileName9").value = document.getElementById("wavName9").innerText;
<p id="YourId">How to use document.GetElementById in HTML</p>
<script>
document.GetElementById('YourId')./* The thing you need to do to your code... Here I want .innerHTML you can take any... */.innerHTML('/* what will it change... */')
</script>