使浏览器tab title 眨眼睛 blink

<script>
    function titlebar(val)
    {
    var msg = "Your message here --- hscripts.com";
    var speed = 500;
    var pos = val;var msg1 = "****** "+msg+" ******";
    var msg2 = "------- "+msg+" -------";if(pos == 0)
    {
    masg = msg1;
    pos = 1;
    }
    else if(pos == 1)
    {
    masg = msg2;
    pos = 0;
    }
    document.title = masg;
    timer = window.setTimeout("titlebar("+pos+")",speed); }
    titlebar(0);
</script>