Cosi
codice:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>Untitled</title>
<script language="JavaScript" type="text/javascript">
<!--
function whoHasFocus() {
document.getElementById('aDiv').innerHTML = document.activeElement.id + " has focus";
} // function whoHasFocus()
//-->
</script>
</head>
<body id="body" onclick="whoHasFocus();">
Clicca in una text box
<input id="t1" type="text" size="20">
<input id="t2" type="text" size="20">
<input id="t3" type="text" size="20">
<hr/>
<div id="aDiv"></div>
</body>
</html>