var zTreeObj;
var setting = {
        callback:{
            onRightClick:zTreeOnRightClick
        }
        
};
var zNodes = [{
    name: "test1",
    open: true,
    children: [{
        name: "test1_1"
    }, {
        name: "test1_2"
    }]
}, {
    name: "test2",
    open: true,
    children: [{
        name: "test2_1"
    }, {
        name: "test2_2"
    }]
}];
$(document).ready(function() {
    zTreeObj = $.fn.zTree.init($("#treeDemo"), setting, zNodes);
});

<div id="rMenu" style="display: none">
    <a href="#" class="rMenuA" onclick="addNode();">增加</a>
    <a href="#" class="rMenuA" onclick="delNode();">删除</a>
    <a href="#" class="rMenuA" onclick="updNode();">修改</a>
</div>

div#rMenu {
    position:absolute; 
    visibility:hidden; 
    top:0; 
    text-align: left;
    padding:4px;
    z-index:999;
}
div#rMenu a{
    padding: 3px 15px 3px 15px;
    background-color:#cad4e6;
    vertical-align:middle;
    text-decoration:none;
}

//右键树结构
function zTreeOnRightClick(event, treeId, treeNode) {
    debugger;
    //alert(111);
     console.log(treeNode);
  //  $("#fileNode_pid").val(treeNode.id);
  //  $("#fileNode_pname").val(treeNode.damc);
    if (!treeNode && event.target.tagName.toLowerCase() != "button" && $(event.target).parents("a").length == 0) {
        showRMenu("root", event.clientX, event.clientY);
    } else if (treeNode && !treeNode.noR) {
          console.log("x="+event.clientX+"y="+event.clientY);
        showRMenu("node", event.clientX, event.clientY);
    }
};

//显示右键菜单
function showRMenu(type, x, y) {
    debugger;
    $("#rMenu").show();
    $("#rMenu").css({"top": y + "px", "left": x + "px", "visibility": "visible"}); //设置右键菜单的位置、可见
    $("body").bind("mousedown", onBodyMouseDown);
}

//隐藏右键菜单
function hideRMenu() {
    $("#rMenu").css({"visibility": "hidden"}); //设置右键菜单不可见
    $("body").unbind("mousedown", onBodyMouseDown);
}
//鼠标按下事件
function onBodyMouseDown(event) {
    if (!(event.target.id == "rMenu" || $(event.target).parents("#rMenu").length > 0)) {
        // $("#rMenu").hide();
        $("#rMenu").css({ "visibility": "hidden"});
    }
}
//增加节点
function addNode(event) {
    alert('增加节点');
}
//删除节点
function delNode(event) {
    alert('删除节点');
}
//修改节点
function updNode(event) {
    alert('修改节点');
}