JSFiddle - React, Tailwind, and code Playground

HTML

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transititonal//EN"
""http://www.w3.org/TR/XHTML1/DTD/xhtml1-transitional.dtd">

<html>
<head></head>
<body>

<form name="TESTING">
<table border="1" width="600" height="200" cellpadding="10" cellspacing="3">
<tr><th colspan="2"><h1>TESTING</h1></th></tr>
<tr>  <th><h3>INPUT</h3></th>
<th><h3>OUTPUT</h3></th>    </tr>
<tr></tr>
<td><input type="number" name="INPUT1"/></td>
<td><input type="text" name="OUTPUT1"></td>
<table>

</form>
</body>
</html>

JavaScript

var input1 = document.getElementsByName("INPUT1")[0];
var output1 = document.getElementsByName("OUTPUT1")[0];

function changeInput(e){ 
    var calc = (((input1.value/20)*0.585)*0.30);
    output1.value = calc;
}

input1.onchange = changeInput;