ction() {
      var input = document.createElement("input");

      input.type = type;
      assert_equals(input.type, type, "the given input type is not supported");

      assert_equals(input.selectionStart, null, 'getting input.selectionStart');
      assert_throws_dom("INVALID_STATE_ERR", function() { input.selectionStart = 0; });
      assert_equals(input.selectionEnd, null, 'getting input.selectionEnd');
      assert_throws_dom("INVALID_STATE_ERR", function() { input.selectionEnd = 0; });
      assert