Js doesn't really care about types, and doesn't seem to convert a string "true" into a boolean true:

    > temp0.innerHTML = true // no error
    > "true" == true
    false
    > true == "true"
    false

The javascript matches are "TypeError" not "Type error", and the more important part of those are "...of null" or "...of undefined". They refer to this:

  var foo = null;
  foo.lastName = "anything"; // TypeError, cannot set property "lastName" of null