How to clear all rows from a grid?

<window title="My First Window" border="normal" width="200px">
<vbox>
<grid id="mygrid">
   <columns>
        <column label="COL1"/>
   </columns>
   <rows id="gridRows">
      <row>
            ROW1
      </row>
      <row>
            ROW2
      </row>
   </rows>
</grid>
<button label="Click Here">
    <attribute name="onClick">
        mygrid.removeChild(gridRows);
        gridRows = new Rows();
        gridRows.setParent(mygrid);
    </attribute>
</button>
</vbox>
</window>