function findLongestWord(str) {
  array = str.split(' ');
  var longest;
  var length = 0;
  for (i = 0; i < array.length; i++) {
    if (array[i].length > length) {
    length = array[i].length;
    longest = array[i];
  }
  }
  return longest.length;
}

findLongestWord("The quick brown fox jumped over the lazy dog");