tbody elementtable element, after any
   caption, colgroup, and
   thead elements, but only if there are no
   tr elements that are children of the
   table element.tr elementsinterface HTMLTableSectionElement : HTMLElement {
  readonly attribute HTMLCollection rows;
  HTMLElement insertRow(optional long index);
  void deleteRow(long index);
};
    The HTMLTableSectionElement interface is also
    used for thead and tfoot elements.
The tbody element represents a block of rows that consist of a body of data for
  the parent table element, if the tbody
  element has a parent and it is a table.
The tbody element takes part in the table
  model.
rowsReturns an HTMLCollection of the tr elements of the table section.
insertRow( [ index ] )Creates a tr element, inserts it into the table section at the position given by the argument, and returns the tr.
The position is relative to the rows in the table section. The index −1, which is the default if the argument is omitted, is equivalent to inserting at the end of the table section.
If the given position is less than −1 or greater than the number of rows, throws an IndexSizeError exception.
deleteRow(index)Removes the tr element with the given position in the table section.
The position is relative to the rows in the table section. The index −1 is equivalent to deleting the last row of the table section.
If the given position is less than −1 or greater than the index of the last row, or if there are no rows, throws an IndexSizeError exception.
The rows attribute
  must return an HTMLCollection rooted at the element,
  whose filter matches only tr elements that are children
  of the element.
The insertRow(index) method must, when invoked on an
  element table section, act as follows:
If index is less than −1 or greater than the
  number of elements in the rows
  collection, the method must throw an IndexSizeError
  exception.
If index is missing, equal to −1, or
  equal to the number of items in the rows collection, the method must
  create a tr element, append it to the element table section, and return the newly created
  tr element.
Otherwise, the method must create a tr element,
  insert it as a child of the table section
  element, immediately before the indexth
  tr element in the rows collection, and finally must
  return the newly created tr element.
The deleteRow(index) method must remove the indexth element in the rows collection from its parent. If
  index is less than zero or greater than or equal
  to the number of elements in the rows collection, the method must
  instead throw an IndexSizeError exception.