document.getelementbyid(elementid).value code example
Example 1: get element by id in javascript
document.getElementById("YourElementId");
Example 2: how to use document.getelementbyid
<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>