var last_keycode=0;

function checkfocus(id1,id2) {
	if (last_keycode>31)  {
		if (document.forms.entercode.elements[id1].value.length==4) {
			document.forms.entercode.elements[id2].focus();		
		}
	}
}

function handle_keydown(event) {
	if (!event) {
		event = window.event;
	}
	if (event.which) {
		last_keycode=event.which;
	} else
	if (event.keyCode) {
		last_keycode=event.keyCode;
	}
}

document.onkeydown = handle_keydown;