var greeting = "";
day = new Date();
hr = day.getHours();

if  ((hr == 23) || (hr == 0) || (hr == 1) || (hr == 2) || (hr == 3) || (hr == 4) || (hr == 5) || (hr == 6))
  greeting = "Buenas Noches! ";

if ((hr == 7) || (hr == 8) || (hr == 9) || (hr == 10) || (hr == 11))
  greeting = "Buenos Días! ";

if ((hr == 12) || (hr == 13) || (hr == 14) || (hr == 15) || (hr == 16)) 
  greeting = "Buenas Tardes! ";

if ((hr == 17) || (hr == 18) || (hr == 19) || (hr == 20) || (hr == 21) || (hr == 22))
  greeting = "Buenas Noches! ";

// End -->