hi,
indem Du Dir per onfocus einen flag setzt.
<html>
<head>
<script language="javascript1.2">
</script>
</head>
<body>
<form name="ups">
<input type="text" name="blah" onfocus="document.ups.aus.value=this.name"><br>
<input type="text" name="lala" onfocus="document.ups.aus.value=this.name"><br>
<input type="text" name="lulu" onfocus="document.ups.aus.value=this.name"><br><br>
<input type="text" name="aus">
</form>
</body>
</html>
Gruesse Joachim