js取treeview checkbox 选中值

Question

protected void Page_Load(object sender, EventArgs e)
        {
            if (!Page.IsPostBack)
            {
               
            TreeView3.Attributes.Add("onclick", "OnTreeNodeChecked('" + TreeView3.ID + "'," + TreeView3.ClientID + ")"); 
        }function OnTreeNodeChecked(controlID,obj) 
{
    tree=obj;    var ele = event.srcElement; 
    if(ele.type=='checkbox'&& ele.checked) 
    { 
    
       这边如何取得checkbox选中时的值    } 
} 如何 用javascript取得treeview中checkbox选中时的值,