function getKeyCode(e)
{
	if (window.event)
		return window.event.keyCode;
	else if (e)
		return e.which;
	else
		return null;
}

function keyRestrict(e, validchars)
{
	var key = getKeyCode(e);
	if (key == null)
		return true;
	var keychar = String.fromCharCode(key);
	keychar = keychar.toLowerCase();
	validchars = validchars.toLowerCase();
	if (validchars.indexOf(keychar) != -1)
		return true;
	if (key==0 || key==8 || key==9 || key==13 || key==27)
		return true;
	return false;
}