function RetornaHora(){ 
        var tmp = document.getElementById("hora").value.split(":"); 
        var s = tmp[2];    var m = tmp[1];    var h = tmp[0]; 
        s++; 
        if (s > 59){ s = 0;    m++; } 
        if (m > 59){ m = 0;    h++; } 
        if (h > 23) h = 0; 
        s = new String(s); if (s.length < 2) s = "0" + s; 
        m = new String(m); if (m.length < 2) m = "0" + m; 
        h = new String(h); if (h.length < 2) h = "0" + h; 
         
        var temp = h + ":" + m + ":" + s; 
        document.getElementById("hora").value = temp; 
    }