<body>
<input id=i><br>
<input>
<script>
        
document.designMode="on";

var e = document.getElementById('i');
e.focus();

if (window.eventSender) {
    var mod = [];
    eventSender.keyDown('\t', mod);
}
</script>
tabbing between forms in design mode (nothing happens at the moment)<br>

</script>