怎么在javascript里控制flash 对象? 比如让他开始和停止,谢谢了! 急

Question

开始：
<TABLE>
<TR>
<TD id=aaa>
<object classid="clsid:D27CDB6E-AE6D-11cf-96B8-444553540000" codebase="http://download.macromedia.com/pub/shockwave/cabs/flash/swflash.cab#version=5,0,0,0" width="760" height="140" id=ccc>
<param name=movie value="show.swf">
<param name=quality value=high><param name="LOOP" value="false">
<embed src="show.swf" quality=high pluginspage="http://www.macromedia.com/shockwave/download/index.cgi?P1_Prod_Version=ShockwaveFlash" type="application/x-shockwave-flash" width="760" height="140" loop="false"  PLAY="true" id=bbb>
</embed> 
</object>
</TD>
</TR>
</TABLE><INPUT TYPE="button" onclick=flash_control() value=开始>
<INPUT TYPE="button" onclick=flash_control() value=结束>
<script>str  = '';
str += '<object classid="clsid:D27CDB6E-AE6D-11cf-96B8-444553540000" codebase="http://download.macromedia.com/pub/shockwave/cabs/flash/swflash.cab#version=5,0,0,0" width="760" height="140">';
str += ' <param name=movie value="show.swf">';
str += ' <param name=quality value=high><param name="LOOP" value="false">';
str += ' <embed src="show.swf" quality=high pluginspage="http://www.macromedia.com/shockwave/download/index.cgi?P1_Prod_Version=ShockwaveFlash" type="application/x-shockwave-flash" width="760" height="140" loop="false">';
str += ' </embed> ';
str += '</object>';
function flash_control()
{
document.all.aaa.innerHTML = str;
}
</script>