selection of one item from ASP.Net ListBox

Where is the dropdown here?. Please post proper code using proper formatting and make use of Code button to add code as said earlier so that we cna understand and read it

     <asp:UpdatePanel ID="UpdatePanel2" runat="server" >
                <ContentTemplate>

<div runat="server" style="position: absolute; z-index: 122; " id="divcity">

 
                            <asp:ListBox ID="drpcity" runat="server" Height="252px"  SelectionMode="Multiple"
                                Width="141px"></asp:ListBox></div>

 </ContentTemplate>
                <Triggers>
                    <asp:AsyncPostBackTrigger ControlID="btnpb" />
                </Triggers>
            </asp:UpdatePanel>



 var list = document.getElementById('drpcity');
            debugger;
            for (var i = 0; i <=list.options.length-1; ++i)
            
             {
             
                if (list.options[i].selected)
                 {
                      
var lstval ;               
                      lstval =  list.options[i].value +","+  lstval  ;
                
                }
            }

Change line 27 to

var lstval  = "";  

ok

after selcting the item i do post back

if agian the listbox is made visible how do i get the initally slected items to  remain  selected  on client side

culd do it on serverside

The values that you set client side you can fetch server side. using

string values = Request.Form[drpcity.UniqueID]

This will give you comma separated values Eg 1.2.5.

You will have to do this way as you are settings values client side