iframe遮盖select

Div 可以遮盖 Iframe

Iframe可以遮盖 Select

Select 可以穿透 Div

所以一般都是用Div遮盖Iframe，Iframe遮盖掉Select来解决 Select 穿透 Div 的问题。

注：z-index:-1

如下:

<div id="win4"  style="z-index:150;border:2px solid #708090; margin-top:150px; width:300px;height:400px;display:none; background-color:#E6E6FA">
<iframe  style="position:absolute;z-index:-1;width:100%;height:100%;top:0;left:0;scrolling:no;filter:progid:DXImageTransform.Microsoft.Alpha(opacity=5);" frameborder="0" src=""></iframe>
<div class="panel-header" onmousedown="CodeSzlg.Move('win4',event,1)" ><div class="mochaCloseButton" onclick="CodeSzlg.closeWin('DIV',{ID:'win4'})"> <b style="margin-right:10px;">&nbsp;× &nbsp; &nbsp; &nbsp; &nbsp;</b></div></div>
<ajax:AjaxPanel ID="AjaxPanel2" runat="server">
<asp:TreeView ID="TreeV_TI_TRADE" Style="width:100%; height:100%; overflow: auto;border:0px" SelectedNodeStyle-Font-Size="Larger" SelectedNodeStyle-BackColor="red" Height="350px" runat="server"
          ExpandDepth="0" Width="260px" ShowLines="True" OnTreeNodeExpanded="TreeV_TI_TRADE_TreeNodeExpanded">
    </asp:TreeView>
</ajax:AjaxPanel>
</div>