控制兄弟frame的大小

<input type="button" value="最大" onclick="parent.document.getElementById('mainframe').rows='0,100%';parent.document.getElementById('mainframe2').cols='0,100%'" /><input type="button" value="还原" onclick="parent.document.getElementById('mainframe').rows='91,100%';parent.document.getElementById('mainframe2').cols='160,100%'" />