關於鼠標移動圖片漸變問題

下面的代碼，我鼠標連續移動的時候，漸變效果不生效，請問應該怎樣修改代碼<html>
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<title>无标题文档</title>
<script language=JavaScript type="text/javascript">function high(which2){theobject=which2
highlighting=setInterval("highlightit(theobject)",10)}
         
function low(which2){theobject=which2
lowlighting=setInterval("lowlightit(theobject)",10)}    
function lowlightit(cur2){if (cur2.filters.alpha.opacity>55)
             
cur2.filters.alpha.opacity -=2
                 
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clearInterval(lowlighting)
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function highlightit(cur2){if (cur2.filters.alpha.opacity<100)
             
cur2.filters.alpha.opacity +=2
                 
else if (window.highlighting)
         
clearInterval(highlighting)
} 
        
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</head><body style="background-color:#ffffff"><p align="center"><a href="www.163.com"><IMG align=middle alt="" border=0 height=88 onmouseout="low(this)" onmouseover="high(this)" src="http://www.fjtjw.com/upfiles/mydown/201002/20100227091917286.jpg" style="FILTER: alpha(opacity=20);" width="170"></a>
</p>
<p align="center"><a href="www.163.com"><IMG align=middle alt="" border=0 height=88 onmouseout="low(this)" onmouseover="high(this)" src="http://www.fjtjw.com/upfiles/mydown/201002/20100227091917286.jpg" style="FILTER: alpha(opacity=20);" width="170"></a>
</p>
<p align="center"><a href="www.163.com"><IMG align=middle alt="" border=0 height=88 onmouseout="low(this)" onmouseover="high(this)" src="http://www.fjtjw.com/upfiles/mydown/201002/20100227091917286.jpg" style="FILTER: alpha(opacity=20);" width="170"></a>
</p>
<p align="center"><a href="www.163.com"><IMG align=middle alt="" border=0 height=88 onmouseout="low(this)" onmouseover="high(this)" src="http://www.fjtjw.com/upfiles/mydown/201002/20100227091917286.jpg" style="FILTER: alpha(opacity=20);" width="170"></a>
</p>
<p align="center"><a href="www.163.com"><IMG align=middle alt="" border=0 height=88 onmouseout="low(this)" onmouseover="high(this)" src="http://www.fjtjw.com/upfiles/mydown/201002/20100227091917286.jpg" style="FILTER: alpha(opacity=20);" width="170"></a>
</p>
</body>
</html></html>