treeView CheckBox选中，checkbox enable=false的字体取消灰色

 <script type="text/javascript">
//入口函数

  function OnCheckEvent() {
            var objNode = event.srcElement;
            if (objNode.tagName != "INPUT" || objNode.type != "checkbox")
                return;
            //获得当前树结点
            var ck_ID = objNode.getAttribute("ID");
            var node_ID = ck_ID.substring(0, ck_ID.indexOf("CheckBox")) + "Nodes";
            var curTreeNode = document.getElementById(node_ID);
            //级联选择
            SetChildCheckBox(curTreeNode, objNode.checked);
            SetParentCheckBox(objNode);
        }

        //子结点字符串
        var childIds = "";
        //获取子结点ID数组
        function GetChildIdArray(parentNode) {
            if (parentNode == null)
                return;
            var childNodes = parentNode.children;
            var count = childNodes.length;
            for (var i = 0; i < count; i++) {
                var tmpNode = childNodes[i];
                if (tmpNode.tagName == "INPUT" && tmpNode.type == "checkbox") {
                    childIds = tmpNode.id + ":" + childIds;
                }
                GetChildIdArray(tmpNode);
            }
        }

        //设置子结点的checkbox
        function SetChildCheckBox(parentNode, checked) {
            if (parentNode == null)
                return;
            var childNodes = parentNode.children;
            var count = childNodes.length;
            for (var i = 0; i < count; i++) {
                var tmpNode = childNodes[i];
                if (tmpNode.tagName == "INPUT" && tmpNode.type == "checkbox") {
                    tmpNode.checked = checked;
                }
                SetChildCheckBox(tmpNode, checked);
            }
        }

        //设置父结点的checkbox
        function SetParentCheckBox(childNode) {
            if (childNode == null)
                return;
            var parent = childNode.parentNode;
            if (parent == null || parent == "undefined")
                return;
            do {
                parent = parent.parentNode;
            }
            while (parent && parent.tagName != "DIV");
            if (parent == "undefined" || parent == null)
                return;
            var parentId = parent.getAttribute("ID");
            var objParent = document.getElementById(parentId);
            childIds = "";
            GetChildIdArray(objParent);
            //判断子结点状态
            childIds = childIds.substring(0, childIds.length - 1);
            var aryChild = childIds.split(":");
            var result = false;
            //当子结点的checkbox状态有一个为true，其父结点checkbox状态即为true,否则为false
            for (var i in aryChild) {
                var childCk = document.getElementById(aryChild[i]);
                if (childCk.checked)
                    result = true;
            }
            parentId = parentId.replace("Nodes", "CheckBox");
            var parentCk = document.getElementById(parentId);
            if (parentCk == null)
                return;
            if (result)
                parentCk.checked = true;
            else
                parentCk.checked = false;
            SetParentCheckBox(parentCk);
        }

    </script>

<div>   
     <asp:TreeView ID="TreeView1" runat="server" ShowCheckBoxes="All" onclick="OnCheckEvent()"
         ShowExpandCollapse="False">
         <Nodes>
             <asp:TreeNode Text="New Node1" Value="New Node1">
                 <asp:TreeNode Text="New Node" Value="New Node">
                     <asp:TreeNode Text="New Node" Value="New Node"></asp:TreeNode>
                 </asp:TreeNode>
             </asp:TreeNode>
             <asp:TreeNode Text="New Node2" Value="New Node2">
                 <asp:TreeNode Text="New Node" Value="New Node"></asp:TreeNode>
                 <asp:TreeNode Text="New Node" Value="New Node">
                     <asp:TreeNode Text="New Node" Value="New Node"></asp:TreeNode>
                 </asp:TreeNode>
             </asp:TreeNode>
             <asp:TreeNode Text="New Node3" Value="New Node3"></asp:TreeNode>
         </Nodes>
     </asp:TreeView>
    </div>

//////不可修改的checkbox的字体取消灰色

$(document).ready(function () {
        $("span").removeAttr("disabled");
    });