/**
   * 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));