swf放大缩小自适应显示

<script type="text/javascript">
function changebig(){
var rate;
var x;
var y;

y = document.getElementById('flashgame1').height;//获取swf高度
x = document.getElementById('flashgame1').width;//获取swf宽度

rate = x/y;
y = y*1.25;
x = y*rate;

document.getElementById('flashgame1').style.height=''+y+'';
document.getElementById('flashgame1').style.width=''+x+''; 
document.getElementById('flashgame1').height=''+y+'';
document.getElementById('flashgame1').width=''+x+'';
 
document.getElementById('flashgame1').Zoom(100);//适应显示

document.getElementById('flashgame1').resize();
}
function changesmall(){
var rate;
var x;
var y;

y = document.getElementById('flashgame1').height;//获取swf高度
x = document.getElementById('flashgame1').width;//获取swf宽度


rate = x/y;
y = y*0.75;
x = y*rate;

document.getElementById('flashgame1').style.height=''+y+'';
document.getElementById('flashgame1').style.width=''+x+''; 
document.getElementById('flashgame1').height=''+y+'';
document.getElementById('flashgame1').width=''+x+'';
 
document.getElementById('flashgame1').Zoom(100);//适应显示

document.getElementById('flashgame1').resize();
}
</script>

<embed id="flashgame1" name="flashgame" 
src="swf文件地址" 
quality="high" pluginspage="http://www.macromedia.com/go/getflashplayer" 
type="application/x-shockwave-flash" width='800' height='480' allowscriptaccess="always" scale: "noScale"
style="width: 800px; height: 480px;">

<p>
<a id="zb_a" onclick="changebig()" href="javascript:void(0)" onfocus="this.blur();" target="_self">放大</a>
<a id="zb_a" onclick="changesmall()" href="javascript:void(0)" onfocus="this.blur();" target="_self">缩小</a>
</p>