Prøv at se nedenstående på
http://morch.dk/kandu.html
<code>
<html xmlns="
http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Untitled Document</title>
<script type="text/javascript">
<!-- Begin
function flytvaerdi(inputfelt,outputfelt)
{
document.getElementById(outputfelt).value = document.getElementById(outputfelt).value + " " + document.getElementById(inputfelt).value;
}
// End -->
</script>
</head>
<body>
<form name="test">
felt1<input type="text" id="felt1" onblur="flytvaerdi('felt1','felt3')" />
felt2<input type="text" id="felt2" onblur="flytvaerdi('felt2','felt3')" />
felt3<textarea id="felt3"></textarea>
</form>
</body>
</html>
</code>