Asp.Net TreeView with CheckBox

1  選擇了父節點,則它的所有子節點都選中
2 只要有一個子節點選中, 其父節點就選中

<script language="javascript" type="text/javascript">function HandleCheckbox()                                           {                                                                                  var element = event.srcElement;                                                if (element.tagName == "INPUT" && element.type == "checkbox")                  {                                                                                  var checkedState = element.checked;                                           while (element.tagName != "TABLE") // Get wrapping table                       {                                                                                  element = element.parentElement;                                           }                                                                                    var parentElement = element;                           if(checkedState)        {         CheckParents(element);        }                                                                                              element = element.nextSibling; //element.tagName = DIV                                                                                       if (element != null) // If no childrens then exit         {                                                                                                                 var childTables = element.getElementsByTagName("TABLE");                         for (var tableIndex = 0; tableIndex < childTables.length; tableIndex++)            {                                                                                      CheckTable(childTables[tableIndex], checkedState);                  }         }        if(checkedState == false)        {            UnCheckParents(parentElement);        }                                                                            }                                                                          }                                                                                                                                                             // Uncheck the parents of the given table, Can remove the recurse (redundant) function CheckParents(table)                                      {                                                                                  if (table == null || table.rows[0].cells.length == 2) // This is the root     {                                                                                  return;                                                                    }                                                                              var parentTable = table.parentElement.previousSibling;    CheckTable(parentTable, true);                                     CheckParents(parentTable);                                    }  // Check the parents of the given table, Can remove the recurse (redundant) function UnCheckParents(table)                                      {                                                                                if (table == null || table.rows[0].cells.length == 2) // This is the root      {                                                                                  return;                                                                    }                                                                        var parentTable = table.parentElement.previousSibling;        var checkedCount  =GetCheckedCount(table.parentElement);    if(checkedCount == 0)    {        CheckTable(parentTable, false);    }                                                     UnCheckParents(parentTable);                                    }                                                                                                                                                             // Handle the set of checkbox checked state                                    function CheckTable(table, checked)     {                                                                                  var checkboxIndex = table.rows[0].cells.length - 1;       var cell = table.rows[0].cells[checkboxIndex];      var checkboxes = cell.getElementsByTagName("INPUT");     if (checkboxes.length == 1)     {                                                                                  checkboxes[0].checked = checked;     }                                                                            }  //Get checked children countfunction GetCheckedCount(table){    var checkedCount = 0;     var element = table.nextSibling;    var childTable = table.getElementsByTagName("TABLE");        for(var tableIndex = 0;tableIndex < childTable.length; tableIndex++)    {        var childTables = childTable[tableIndex];        var checkboxIndex = childTables.rows[0].cells.length - 1;            var cell = childTables.rows[0].cells[checkboxIndex];          var checkboxes = cell.getElementsByTagName("INPUT");        if (checkboxes.length == 1 && checkboxes[0].checked == true)        {                                                                                       checkedCount++;                    }          }       return  checkedCount;   }                                                                             </script><asp:TreeView ID="TreeViewModules" runat="server" ShowCheckBoxes="All" onclick="HandleCheckbox();"        ShowLines="True" ExpandDepth="1" meta:resourcekey="TreeViewModulesResource1"></asp:TreeView>