拉斐尔.js - 交换文本中的字符(动画)

var paper = Raphael("holder", 700, 300);
    var messageText = "Why don't try yourself before asking your question?";
    messageText = Swap(messageText);
    var msg = paper.text(0, 20, messageText).attr({ "text-anchor": "start", "font-size": 21, "font-family": "Courier New" });
    function Swap(text) {
      return text.split('').reverse().join('');
    }
    var array = messageText.split("");
    var loopTimer;
    msg[0].textContent = '';
    function Looper() {
      if (array.length > 0) {
        msg[0].textContent += array.shift();
      } else {
        clearTimeout(loopTimer);
        return false;
      }
      loopTimer = setTimeout('Looper()', 70);
    };
    Looper();
    setTimeout(function () {
      messageText = Swap(messageText);
      array = messageText.split("");
      msg[0].textContent = '';
      Looper();
    }, 100 * messageText.length);