how can i get value of node in treeview when checkbox is checked in asp.net by jquery

[FHN]

i have a simple asp:treeview\[code\]<asp:TreeView ID="TreeView1" runat="server" ShowCheckBoxes="Leaf" OnTreeNodeCheckChanged="CheckChanged" ShowLines="true" PopulateNodesFromClient="true" ShowExpandCollapse="true" NodeIndent="10"> </asp:TreeView>\[/code\]and i do this\[code\]<script type="text/javascript"> function client_OnTreeNodeChecked(event) { var treeNode = event.srcElement || event.target; if (treeNode.tagName == "INPUT" && treeNode.type == "checkbox") { if (treeNode.checked) { alert(treeNode.value); } } } </script>\[/code\]but i only get "on" in alert.how can i get value of node instead of value of checkbox?