js实现点中子节点父节点自动选中

 <script type="text/javascript" language="javascript">
     function setParentState(objNode) {
        var objParentDiv = WebForm_GetParentByTagName(objNode, "div");
        if (objParentDiv == null || objParentDiv == "undefined")
            return;

        var divID = objParentDiv.getAttribute("ID");
        var prefix = divID.substring(0, divID.indexOf("Nodes"));
        var parentID = prefix + "CheckBox";

        var parentChk = document.getElementById(parentID);
        if (parentChk == null || parentChk == "undefined")
            return;

        if (objNode.checked) {
            parentChk.checked = true;
        }
        else {
            if (isAllChildrenUnChecked(parentChk)) {
                parentChk.checked = false;
            }
        }

        setParentState(parentChk);
    }

    function setChildState(objNode)//设定子控件状态
    {
        var nodeID = objNode.getAttribute("ID");   //chkBox ID
        var prefix = nodeID.substring(0, nodeID.indexOf("CheckBox"));  //节点的前缀
        var childrenDiv = document.getElementById(prefix + "Nodes");

        if (childrenDiv == null || childrenDiv == "undefined")
            return;

        var childrenArray = childrenDiv.children; //取得所有子控件

        for (var i = 0; i < childrenArray.length; i++) {
            var container = childrenArray[i]; //子控件的容器
            var chk = WebForm_GetElementByTagName(container, "input"); //查找Check控件,由于只有一个种Input控件,就是CheckBox
            chk.checked = objNode.checked;

            setChildState(chk);

        }

    }

    function isAllChildrenUnChecked(objChk) {
        var objChkID = objChk.getAttribute("ID");
        var prefix = objChkID.substring(0, objChkID.indexOf("CheckBox"));  //节点的前缀
        var childrenDiv = document.getElementById(prefix + "Nodes");

        if (childrenDiv == null || childrenDiv == "undefined")
            return;

        var childrenArray = childrenDiv.children; //取得所有子控件

        for (var i = 0; i < childrenArray.length; i++) {
            var container = childrenArray[i]; //子控件的容器
            var chk = WebForm_GetElementByTagName(container, "input"); //查找Check控件,由于只有一个种Input控件,就是CheckBox

            if (chk.checked)
                return false;
        }
        return true;
    }

    //触发事件
    function HandleCheckEvent() {

        var objNode = event.srcElement;

        if (objNode.tagName != "INPUT" || objNode.type != "checkbox")
            return;

        //设定子Chk状态
        setChildState(objNode);
        //设定父Chk状态
        setParentState(objNode);

    }
    </script>