function restrictToDigits(e)
{
    if (!e) e = window.event;

    var kp = null;    
    if (e.keyCode) kp = e.keyCode;
    else if (e.which) kp = e.which;

    if (!kp) return true;

    return !(kp > 31 && kp < 128 && (kp < 48 || kp > 57));
}

function restrictToDigitsAndMove(e,len,target)
{
    if (!e) e = window.event;
    var tb = null;
    if (e.target) tb = e.target;
    else if (e.srcElement) tb = e.srcElement;

    if (!tb) return true;

    var kp = null;    
    if (e.keyCode) kp = e.keyCode;
    else if (e.which) kp = e.which;

    if (!kp) return true;

    if (kp > 31 && kp < 128 && (kp < 48 || kp > 57))
        return false;

    if (kp > 47 && kp < 58 && tb.value.length >= len)
        $get(target).focus();

    return true;
}