<script>
function myReverse(){
document.getElementById('MyStringIn').innerHTML=document.getElementById('MyStringOut').value
let myIn = document.getElementById('MyStringIn')
let myOut= document.getElementById('MyStringOut')
myOut.innerHTML = innerHTML.(reverseString('myIn')
}
</script>
<input type="text" value="Input" id="MyStringIn">...</div>
<div id="MyStringOut">Output</div>
<input value="Reverse value of ..." type="button" onclick="{myReverse()}>