Using two iFrame in the same page is not working in firefox

I'm using two iframes in my page one for menu page and another for some default page. So, I used two iframes for loading the external pages. It is working fine in IE. But, not in firefox. The second iframe is not displayed. Please help me out.

<table id="tbleMain" width="100%" align="left"  >
                <tr align="left" style="width: 10%; height: 10%">
                    <td align="left" colspan="2">
                        <img src="../Images/Log开发者_StackOverflow社区o.JPG" height="70px" width="1000px"/>
                    </td>
                </tr>
                <tr style="height:  90%">
                    <td width="3%">
                        <iframe id="frame1" name="f1" align="left" frameborder="0" width="200px" height="500px" src="Menu.jsp"/>
                    </td>
                    <td width="97%" valign="top" align="left">

                            <iframe id="frame2" name="f2" align="left" frameborder="0" width="200px" height="500px" src="SrchEnv.jsp"/>

                    </td>
                </tr>

            </table>

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change your first iframe tags like below:

<iframe id="frame1" name="f1" align="left" frameborder="0" width="200px" height="500px" src="Menu.jsp"></iframe>

It should be ok,but I don't know why it run in this way.