How to post image and text to web page with javascript

[comdec]

I am using a webtree control to control events on the web page. My problem is when I click on a child in the webtree I can identify the index, but I am having a problem posting that index to the code-behind file or the web page.

Here is my code

function AfterNodeSelChange(treeId, nodeId, button) {
 
        var node = igtree_getNodeById(nodeId);
        if(node == null)
            return;
 
       var eventName = node.getText(); //Get the node text
      // alert(eventName);
       var EvName;  // evenet process name
       var nIndex;   // get the county index
          switch(eventName)
          {
            // Appling County
           case "APPLING":    //Get Appling county-now activate search
            {
 
               nIndex = node.getIndex();
               if(nIndex == 0)
                 {
                    var ZIndex = documment.
                   alert(nIndex);   // for debug purpose
          //  this code does not work to post an image on the web page. 
          // or change the text on the label - Can you help???????????
                   txtName.Text = "Appling"; 
    var NameImg =  document.getElementById("ImgCounty");
       NameImg.ImgeUrl="./images/appling.gif";
     var nameCnty =document.getElementById("lblCounty");
         nameCnty.Text="APPLING;
        //
                 }
             }
         }
 

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I want to post that index in this C# function

    protected void sRTree_NodeClicked(object sender, Infragistics.WebUI.UltraWebNavigator.WebTreeNodeEventArgs e)
    {
 
        string nIndex = String.Empty;
   MIISING IS THE CODE TO ACCESS THAT INDEX IN JAVASCRIPT
 
    //    cNode = this.sRTree.Nodes.Index(nIndex);
        switch(ZIndex)
        {
            case 0: // "APPLING":
                {
                  ZIndex = 0;
                  nIndex = string.Empty;
                  ImgCounty.ImageUrl = "./Counties/Appling.gif";
                  lblCounty.Text = "Appling";
                  txtScrhCounty.Text = "Appling";
                }
        }
 }