js打印问题请教

[miaoyu04]

<frameset rows="95,76%,60" border="0" frameSpacing="0" frameBorder="0">
        <frame name="header" src="Top.aspx" scrolling="no" noresize style="BORDER-RIGHT: #0099ff 2px ridge; BORDER-TOP: #0099ff 2px ridge; BORDER-LEFT: #0099ff 2px ridge; BORDER-BOTTOM: #0099ff 2px ridge">
        <frameset cols="200,*" id="middle">
            <frame name="contents" src="LeftFrame.aspx" style="BORDER-RIGHT: #0099ff 2px ridge; PADDING-RIGHT: 2px; BORDER-TOP: #0099ff 3px; PADDING-LEFT: 2px; MARGIN-LEFT: 2px; BORDER-LEFT: #0099ff 2px ridge; MARGIN-RIGHT: 2px; BORDER-BOTTOM: #0099ff 3px">
            <frame name="main" src="Main.aspx" scrolling="auto" style="BORDER-RIGHT: #0099ff 2px ridge; PADDING-RIGHT: 2px; BORDER-TOP: #0099ff 1px; BORDER-LEFT: royalblue 3px; MARGIN-RIGHT: 2px; BORDER-BOTTOM: royalblue 1px">
        </frameset>
        <frame name="footer" src="Bottom.aspx" scrolling="no" style="BORDER-RIGHT: #0099cc 2px ridge; BORDER-TOP: #0099cc 2px ridge; BORDER-LEFT: #0099cc 2px ridge; BORDER-BOTTOM: #0099cc 2px ridge">
    </frameset>

问题：在上面的框架集里，如何实现“打印预览”或“直接打印”时只打印<frame name="main">部分的内容？

[dh20156]

調用main的window中的打印或預覽的腳本！

[miaoyu04]

谢谢一楼的回复，能不能给个例子啊。