<!--
This is example is with a number...
But you can do it with whatever input type you want
-->
<input type="number" name="numberInput" id="numberInput" max="20" min="1" step="1">
<button type="button" onclick="myFunction()">sumbit</button>
<script>
function myFunction() {
let tokenAmount = document.getElementById("numberInput").value;
return // whatever you want to do with it
}
</script>