[求助]下拉表单控制层显示的问题....

这是改之前的代码，运行的非常好 :(
<HTML>
<HEAD ID="Header" >
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Welcome</title>
<style type="text/css">
</style>
</HEAD>

解决方案 »

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<BODY>
<DIV class="FixPageWidth">
  <TABLE cellpadding="0" cellspacing="0" class="Table1">
    <TR>
      <TD class="TD_valign_top content">
      <DIV id="Middle" >
            <DIV id="CheckoutSteps_SubHeader">
              <DIV id="CheckoutSteps_SubHeader_Title">
                <DIV id="TAB_CreditCard" onClick="showDiv('CreditCard')">111 </DIV>
                <DIV id="TAB_PurchaseOrder" onClick="showDiv('PurchaseOrder')"> 222</DIV>
                <DIV id="TAB_RequestForQuote" onClick="showDiv('RequestForQuote')"> 333</DIV>
                <DIV id="TAB_RequisitionApproval" onClick="showDiv('RequisitionApproval')">444 </DIV>
              </DIV>
              <DIV id="CheckoutSteps_SubHeader_Step4"> </DIV>
              <DIV class="CheckoutSteps_Underline"> </DIV>
            </DIV>
            <DIV id="CheckoutSteps_EditSection">

              <FORM id="frmCreditCard" action="index.aspx?Command=CreditCardPost" method="post" onSubmit="return validateOnSubmit()">
                <DIV id="pmt_CreditCard">
                <SPAN class="payMethodInfo"> <SPAN class="txtCont"> You have chosen to checkout using a <SPAN class="Note-Emphasis1">Credit Card</SPAN>.
                  <DIV class="Line1_Middle"> </DIV>
                  <DIV class="divInst">
                    <P> <SPAN class="txtHead">Instructions:</SPAN> </P>
                    Type in your credit card information and then click <SPAN class="txtCont">Continue</SPAN>. </DIV>
                  <BR>
                   <SCRIPT>
                        F = document.forms['frmCreditCard'];
                        setSelected(F.CardType, '');
                        setSelected(F.ExpiryMonth, '');
                        setSelected(F.ExpiryYear, '');
                      </SCRIPT>
                </DIV>
              </FORM>

              <FORM id="frmPurchaseOrder" action="index.aspx?Command=PurchaseOrderPost" method="post">
                <DIV id="pmt_PurchaseOrder" style="display:none">
                 <SPAN class="payMethodInfo"> <SPAN class="txtCont"> You have chosen to checkout using a <SPAN class="Note-Emphasis1">Purchase Order</SPAN>.
                  To checkout using a

                  Credit Card,
                  Request For Quote or
                  Requisition Approval;
                  please click one of the tabs above. </SPAN> </SPAN>
                  <DIV class="Line1_Middle"> </DIV>
                  <DIV class="divInst"> <SPAN class="txtHead">Instructions:</SPAN> <BR>
                    <BR>
                    <SPAN class="txtHead">Purchase Order - Open Account</SPAN> <BR>
                    <BR>
                    We will gladly process your Purchase Order. Our terms are net 30 days to approved credit.<BR>
                    We will extend credit to businesses only. Once credit is approved, a confirmation email will be<BR>
                    sent with approximate shipping date. Invoice mailed separately within two days of shipment.<BR>
                    <BR>
                    <SPAN class="txtHead">New Accounts</SPAN><BR>
                    To open a credit account, download our <A href="common/pdfs/new accounts.pdf">PDF application</A> and fax it back to ,<BR>
                    Attn: Customer Service. Completed Applications will be processed immediately to ensure future<BR>
                    orders have open account terms. Our standard terms are net 30 days. <BR>
                    <BR>
                  </DIV>
                 </DIV>
              </FORM>

              <FORM id="frmRequestForQuote" style="margin-bottom:0; margin-top:0" action="index.aspx?Command=RequestForQuotePost" method="post">
                <DIV id="pmt_RequestForQuote" style="display:none">
                <SPAN class="payMethodInfo"> <SPAN class="txtCont"> You have chosen to checkout using a <SPAN class="Note-Emphasis1">Request For Quote</SPAN>.
                  To checkout using a

                  Credit Card,
                  Purchase Order or
                  Requisition Approval;
                  please click one of the tabs above. </SPAN> </SPAN>
                  <DIV class="Line1_Middle"> </DIV>
                  <DIV class="divInst"> <SPAN class="txtHead">Instructions:</SPAN> <BR>
                    <BR>
                    To submit your order as a Request for Quote, click the <B>Finish Order</B> button on the summary page.
                    We will contact you with details on item costs, shipping and tax information.<BR>
                    <BR>
                  </DIV>
                  <INPUT name="btnContinue" type="submit" value="" class="btnContinue">
                </DIV>
              </FORM>

              <FORM id="frmRequisitionApproval" style="margin-bottom:0; margin-top:0" action="index.aspx?Command=RequisitionApprovalPost" method="post">
                <DIV id="pmt_RequisitionApproval" style="display:none">
                 <SPAN class="payMethodInfo">
                  <SPAN class="txtCont"> You have chosen to checkout using a <SPAN class="Note-Emphasis1">Requisition Approval</SPAN>.
                  To checkout using a

                  Credit Card,
                  Purchase Order or
                  Request For Quote;
                  please click one of the tabs above. </SPAN> </SPAN>
                  <DIV class="Line1_Middle"> </DIV>
                  <DIV class="divInst"> <SPAN class="txtHead">Instructions:</SPAN> <BR>
                    <BR>
                    <SPAN class="txtHead">Fax Requisition</SPAN> – The Order Requisition form allows you to obtain any necessary signatures for your order.<BR>
                    The Requisition is then faxed to us.<BR>
                    <BR>
                    <DIV><B>Here is how it works:</B><BR>
                      <BR>
                      <BR>
                      1) When you click <SPAN class="txtCont">Continue</SPAN> below you will be taken to the <B>Summary</B> Page<BR>
                      <BR>
                      2) On the Summary page, click <B>Finish Order</B>.<BR>
                          <B>Note:</B> You can add any order comments on this page in the blue box.<BR>
                      <BR>
                      3) A <B>Fax Form Icon</B> is shown. Click on this Icon.<BR>
                      <BR>
                      4) The Order Requisition can now be printed. Fax the order to the number shown on the form.<BR>
                      <BR>
                    </DIV>
                  </DIV>
                  <INPUT name="btnContinue" type="submit" value="" class="btnContinue">
                </DIV>
              </FORM>
            </DIV>
          </DIV>
          <SCRIPT>

      selOpt = '';
      Options = ['CreditCard', 'PurchaseOrder', 'RequestForQuote', 'RequisitionApproval'];
      for(i = 0; i < Options.length; i++)
       if(document.getElementById('TAB_' + Options[i]) !== null)
       {
        selOpt = Options[i];
        document.getElementById('TAB_' + selOpt).id = 'TAB_' + selOpt + '_active';
        document.getElementById('pmt_' + selOpt).style.display = 'block';
        break;
       }

      function showDiv(divOpt)
      {
       document.getElementById('TAB_' + selOpt + '_active').id = 'TAB_' + selOpt;
       document.getElementById('pmt_' + selOpt).style.display = 'none';
       selOpt = divOpt;
       document.getElementById('TAB_' + selOpt).id = 'TAB_' + selOpt + '_active';
       document.getElementById('pmt_' + selOpt).style.display = 'block';
      }

    </SCRIPT>
        </TD>
    </TR>
  </TABLE>
</DIV>
</BODY>
</HTML>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Welcome</title><style type="text/css">

</style>
</head>
<body>

   <SELECT name="selectid" class="SelectP" onchange="showDiv(document.all.selectid.value)">
<option value="1" >>> Layer1</option>
<option value="2" >>> Layer2</option>
<option value="3" >>> Layer3</option>
<option value="4" >>> Layer4</option>
</SELECT>


<div id="EditSection"><br>Layer1.ddd<br></div>

<div id="pmt_2"><br>Layer2  Layer2  .<br></div>
<div id="pmt_3"><br>Layer3  Layer3  Layer3 <br></div>
<div id="pmt_4"><br>Layer4  Layer4  Layer4  Layer4 <br></div>
<div id="pmt_1"><br>Lasdfasyer1.ddd<br></div>

      <SCRIPT>
      function showDiv(divOpt)
      {
  //alert(document.getElementById('pmt_' + divOpt).outerHTML);
   document.getElementById('EditSection').innerHTML = document.getElementById('pmt_' + divOpt).innerHTML;
      }

    </SCRIPT>
       </div>
</body>
</html>
谢谢，不过这个在IE里OK，但是firfox里不行啊？？
合适FireFox和IE的下拉表单控制切换层，这个问题很难吗？
还是，太简单了不屑于回答呢？