scramble.js

var brand = document.getElementById('brand');

var intervals = [];

function scramble(element, text, time) {
  var length = element.innerText.length;
  var diff = (length - text.length) * -1;
  var count = 0;
  var lettersPerIteration = 0;
  if (diff !== 0) {
    lettersPerIteration = diff / time;
  }
  var eleId = element.id;
  clearInterval(intervals[eleId]);
  var tempText = '';
  intervals[eleId] = setInterval(function() {
    tempText = getRandomString(Math.round(length));
    length += lettersPerIteration;
    element.innerHTML = tempText;
    if (count++ > time) {
      clearInterval(intervals[eleId]);
      element.innerHTML = text;
    }
  }, 35);
}

function getRandomString(length) {
  var priv = {};
  priv.consonants = ['b', 'c', 'd', 'f', 'g', 'h', 'j', 'k', 'l', 'm', 'n', 'p', 'r', 's', 't', 'v', 'w'];
  priv.vowels = ['a', 'e', 'i', 'o', 'u', ' '];
  priv.result = '';
  priv.getLetter = function(datasource) {
    var key = Math.floor(Math.random() * datasource.length);
    return datasource[key];
  }
  var loopStat = 0;
  if (!length) {
    length = 6;
  }
  while (loopStat < length) {
    if (loopStat === null || loopStat % 2) {
      priv.result += priv.getLetter(priv.vowels);
    } else {
      priv.result += priv.getLetter(priv.consonants);
    }
    loopStat++;
  }
  return priv.result;
}

// scramble(brand, 'Instrumental Study', 6);