var changeRate = 2000; // 1000 = 1 second
var messageNumber = 0;

function changeStatus() {
  if (messageNumber == 0) {
     document.title=default1;
    }
  else if (messageNumber == 1) {
     document.title=text1;
    }
  else if (messageNumber == 2) {
     document.title=text2;
     }
  else if (messageNumber == 3) {
     document.title=text3;
     messageNumber = 0;
     }

  messageNumber++;
  setTimeout("changeStatus();",changeRate);

}

changeStatus();