/**

         * 将list装换成tree

         * @param {Object} myId  数据主键id

         * @param {Object} pId     数据关联的父级id

         * @param {Object} list list集合

         */

        function listToTree(myId,pId,list){

            function exists(list, parentId){

                for(var i=0; i<list.length; i++){

                    if (list[i][myId] == parentId) return true;

                }

                return false;

            }

            var nodes = [];

            // get the top level nodes

            for(var i=0; i<list.length; i++){

                var row = list[i];

                if (!exists(list, row[pId])){

                    nodes.push(row);

                }

            }

            var toDo = [];

            for(var i=0; i<nodes.length; i++){

                toDo.push(nodes[i]);

            }

            while(toDo.length){

                var node = toDo.shift();    // the parent node

                // get the children nodes

                for(var i=0; i<list.length; i++){

                    var row = list[i];

                    if (row[pId] == node[myId]){

                        //var child = {id:row.id,text:row.name};

                        if (node.children){

                            node.children.push(row);

                        } else {

                            node.children = [row];

                        }

                        toDo.push(row);

                    }

                }

            }

            return nodes;

        }

        var list=[

            {"ids":1,"parendId":0,"name":"Foods",url:"wwww"},

            {"ids":2,"parentId":1,"name":"Fruits"},

            {"ids":3,"parentId":1,"name":"Vegetables"},

            {"ids":4,"parentId":2,"name":"apple"},

            {"ids":5,"parentId":2,"name":"orange"},

            {"ids":6,"parentId":3,"name":"tomato"},

            {"ids":7,"parentId":3,"name":"carrot"},

            {"ids":8,"parentId":3,"name":"cabbage"},

            {"ids":9,"parentId":3,"name":"potato"},

            {"ids":10,"parentId":3,"name":"lettuce"},

            {"ids":11,"parendId":0,"name":"Foods"},

            {"ids":12,"parentId":11,"name":"Fruits"},

            {"ids":13,"parentId":11,"name":"Vegetables"},

            {"ids":14,"parentId":12,"name":"apple"},

            {"ids":15,"parentId":12,"name":"orange"},

            {"ids":16,"parentId":13,"name":"tomato"},

            {"ids":17,"parentId":13,"name":"carrot"},

            {"ids":18,"parentId":13,"name":"cabbage"},

            {"ids":19,"parentId":13,"name":"potato"},

            {"ids":20,"parentId":13,"name":"lettuce"}

        ];

      console.log(JSON.stringify(listToTree("ids","parentId",list)));

      console.log(listToTree("ids","parentId",list));