Functin for Moving Title of Page in JavaScript

<script type="text/javascript">
    var rev = "fwd";
    function titlebar(val) {
        var msg = "Welcome To IndiaMART WebERP";
        var res = " ";
        var speed = 100;
        var pos = val;

        //msg = "   |--- " + msg + " ---|";
        var le = msg.length;
        if (rev == "fwd") {
            if (pos < le) {
                pos = pos + 1;
                scroll = msg.substr(0, pos);
                document.title = scroll;
                timer = window.setTimeout("titlebar(" + pos + ")", speed);
            }
            else {
                rev = "bwd";
                timer = window.setTimeout("titlebar(" + pos + ")", speed);
            }
        }
        else {
            if (pos > 0) {
                pos = pos - 1;
                var ale = le - pos;
                scrol = msg.substr(ale, le);
                document.title = scrol;
                timer = window.setTimeout("titlebar(" + pos + ")", speed);
            }
            else {
                rev = "fwd";
                timer = window.setTimeout("titlebar(" + pos + ")", speed);
            }
        }
    }

    titlebar(0);
</script>