Hi there petermarsi,
and a warm welcome to these forums. :o
Here is a possible solution...
<!DOCTYPE HTML>
<html lang="en">
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width,height=device-height,initial-scale=1">
<title>Untitled document</title>
<!--
The internal CSS should be transferred to an external file
<link rel="stylesheet" href="screen.css" media="screen">
-->
<style media="screen">
body {
background-color: #f0f0f0;
font: normal 1em / 1.5em sans-serif;
}
h1,h2 {
line-height: 1em;
color: #555;
text-align: center;
text-transform: capitalize;
}
form {
display: flex;
flex-direction: column;
align-items: center;
max-width: 30em;
padding: 1em;
margin: auto;
border: 1px solid #999;
background-color: #fff;
box-shadow: 0.4em 0.4em 0.4em rgba( 0, 0, 0, 0.4 );
}
label{
display: inline-block;
width: 6em;
}
input[type="text"] {
width: 100%;
max-width:16em;
margin: 0.75em 0;
}
</style>
</head>
<body>
<h1>page description</h1>
<form action="#">
<h2>select colour</h2>
<div>
<input id="r0" name="r" type="radio" value="Red">
<label for="r0">Red</label>
</div>
<div>
<input id="r1" name="r" type="radio" value="Blue">
<label for="r1">Blue</label>
</div>
<div>
<input id="r2" name="r" type="radio" value="Yellow">
<label for="r2">Yellow</label>
</div>
<input id="inp0" name="colour" type="text" readonly>
<button>submit</button>
</form>
<!--
The internal JavaScript should be transferred to an external file
<script src="your-filename.js"></script>
-->
<script>
(function(d) {
'use strict';
var labs = d.querySelectorAll( 'label' );
var rads = d.querySelectorAll( 'input[name="r"]' );
for ( var c = 0; c < rads.length; c ++ ) {
rads[c].addEventListener( 'click', changeValue(c), false );
}
function changeValue(c) {
rads[c].onclick = function() {
d.querySelector( '#inp0' ).value = labs[c].textContent;
};
}
}(document));
</script>
</body>
</html>
coothead