How does jquery traverse and obtain the list collection from the background?

In the project, jquery obtains the list from the background. How does it traverse it?

Under normal circumstances, the list in the background should be converted into a json string and returned to the callback function of ajax. The json string can be directly manipulated in the callback function.

For example:

$.post("test.php", { name: "John", time: "2pm" },

function(data){
  //可以在这儿循环，比如：
  var listNow=data.listHouTai;//取list。listHouTai是你后台定义的json名称
  for ( var i = 0; i < listNow.length; i++) { 
       var id = vos[i].Id;//可以取list中第一个对象的id值，其他的类推
  ｝         
});

You can use a jQuery custom array operation classjs external file, the prerequisite is to introduce the jQuery class library. The encapsulation class code is as follows:

(function ($) {
    $.List = function () {
        var _list = new Array();
        //外部为数组赋值
        this.GetDataSource = function (arr) {
            if (IsArrayType(arr)) {
                _list = arr;
            } else {
                alert("指定元素非数组类型，赋值失败！");
            }
        };
        //添加一个元素
        this.Add = function (arg) {
            if (arg) {
                _list.push(arg);
            } else {
                alert("参数错误，添加元素失败！");
            }
            return _list;
        };
        //删除指定索引的元素
        this.RemoveAt = function (index) {
            if (IsArrayIndex(index) && index < _list.length) {
                var i;
                var arr = new Array();
                for (i = 0; i < _list.length; i++) {
                    if (i != index) {
                        arr.push(_list[i]);
                    }
                }
                _list = arr;
                return _list;
            }
            else {
                alert("未获取到设置对象的实例，删除元素失败！");
            }
        };
        //按照指定的分割符显示出所有元素
        this.Split = function (arg) {
            arg = arg || ",";
            var i, res;
            res = "";
            if (_list.length > 0) {
                for (i = 0; i < _list.length; i++) {
                    res += _list[i].toString() + arg;
                }
                return res.substr(0, (res.length - arg.toString().length));
            } else {
                return "";
            }
        };
        //外部调用直接返回当前数组实力
        this.ToArray = function () {
            return _list;
        };
        //设置指定索引处的值为指定值
        this.Update = function (index, value) {
            if (IsArrayIndex(index) && index < _list.length) {
                _list[index] = value;
            }
            return _list;
        };
        //清空所有元素
        this.RemoveAll = function () {
            _list.splice(0, _list.length);
            return _list;
        };
        //根据传入的值获取第一次出现在数组中的下标
        this.IndexOf = function (value) {
            if (value) {
                var i;
                for (i = 0; i < _list.length; i++) {
                    if (_list[i] == value) {
                        return i;
                    }
                }
            }
            return -1;
        };
        //获取数组长度
        this.Size = function () {
            return _list.length;
        };
        //移除数组中重复的项
        this.RemoveRepeat = function () {
            _list.sort();
            var rs = [];
            var cr = false;
            for (var i = 0; i < _list.length; i++) {
                if (!cr)
                    cr = _list[i];
                else if (cr == _list[i])
                    rs[rs.length] = i;
                else
                    cr = _list[i];
            }
            for (var i = rs.length - 1; i >= 0; i--)
                this.RemoveAt(rs[i]);
            return _list;
        };
        //对数字数组元素排序，参数：0升序1降序
        this.SortNumber = function (f) {
            if (!f) f = 0;
            if (f == 1) return _list.sort(function (a, b) { return b - a; });
            return _list.sort(function (a, b) { return a - b; });
        };

        //私有方法
        //判断正确的数组下标
        function IsArrayIndex(index) {
            var reg = /^\d+$/;
            if (reg.test(index))
                return true;
            else
                return false;
        }
        //判断当前对象是否为数组对象
        function IsArrayType(arr) {
            if (typeof arr == &#39;object&#39; && typeof arr.length == &#39;number&#39;)
                return true;
            else
                return false;
        }
    }; //结束List的构造方法

})(jquery);

Two js files need to be introduced when calling the page:

<script src="js/jquery-1.8.3.min.js" type="text/JavaScript"></script>
<script src="js/jquery.array.js" type="text/javascript"></script>
<script type="text/javascript">
 $(function () {
            var myList = new $.List();
            myList.Add(1);
            myList.Add("1906-07-08");
            myList.Add("hellow world");
            myList.RemoveAt(0);
            myList.Update(0, "11111111");
            //alert("数组被修改内容后的结果：" + myList.Split("|"));
            myList.RemoveAll();
            var arr = myList.ToArray();
            //alert("数组全部被删除后结果：" + arr);
            //alert("数组1当前长度：" + myList.Size());
            var myList2 = new $.List();
            myList2.Add(3);
            myList2.Add(1);
            myList2.Add(45);
            myList2.Add(21);
            myList2.Add(-9);
            myList2.Add(1);
            alert("第二个实例数组结果：" + myList2.ToArray());
            myList2.RemoveRepeat();
            alert("去重后第二个实例数组结果：" + myList2.ToArray());
            alert("去重后第二个实例数组长度：" + myList2.Size());
            myList2.SortNumber(1);
            alert("排序后的数组：" + myList2.ToArray());
            var arr3 = ["aaa", "bbb", "ccc", "ddd", "eee"];
            var arr4;
            myList2.GetDataSource(arr3);
            alert("重新赋值后结果："+myList2.ToArray());
        });
    </script>

Object syntax JSON data format (when the server calls back The object data format is json data format, and the format requirements of JSON must be met. The callback object must be converted using the eval function (otherwise, the Object will not be obtained). This article will not introduce the data issues of the server-side callback in detail. We will directly customize the object. )

1.jqueryTraverse the object

< !DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" > <HTML > <HEAD > <TITLE > New Document < /TITLE>
  <script language="javascript" type="text/javascript " src="jquery.min.js "></script>
  <script  type="text / javascript ">
     $(function(){
       var tbody = "";    
    //------------遍历对象 .each的使用-------------
    
    var obj =[{"name ":"项海军","password ":"123456 "}];
   $("#result ").html("------------遍历对象.each的使用-------------");
      alert(obj);//是个object元素
   //下面使用each进行遍历
   $.each(obj,function(n,value) { 
           alert(n+&#39; &#39;+value);
           var trs = "";
             trs += " < tr > <td > " + value.name +" < /td> <td>" + value.password +"</td > </tr>";
             tbody += trs;       
           });
         $("#project").append(tbody);
     
  });
  </script > </HEAD>
 
 <BODY>
     <div id="result" style="font-size:16px;color:red;"></div > <table cellpadding = 5 cellspacing = 1 width = 620 id = "project"border = "1" > <tr > <th > 用户名 < /th>
                <th>密码</th > </tr>             
     </table > </BODY>
</HTML >

2.jQueryTraverse the array

< !DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" > <HTML > <HEAD > <TITLE > New Document < /TITLE>
  <script language="javascript" type="text/javascript " src="jquery.min.js "></script>
  <script  type="text / javascript ">
     $(function(){
       var tbody = "";
    
     //------------遍历数组 .each的使用-------------
           var anArray = [&#39;one&#39;,&#39;two&#39;,&#39;three&#39;];
     $("#result ").html("------------遍历数组.each的使用-------------");
           $.each(anArray,function(n,value) {
           
            alert(n+&#39; &#39;+value);
           var trs = "";
             trs += " < tr > <td > " +value+" < /td></tr > ";
              tbody += trs;
            });
          $("#project ").append(tbody);
     
  });
  </script>
 </HEAD>
 
 <BODY>
    ------------此部分同1中的body部分--------------------
 </BODY>
</HTML>
3.jQuery 遍历List集合（其实与遍历一个对象没有太大区别，只是格式上的问题）
<!DOCTYPE HTML PUBLIC " - //W3C//DTD HTML 4.0 Transitional//EN">
< HTML > <HEAD > <TITLE > New Document < /TITLE>
  <script language="javascript" type="text/javascript " src="jquery.min.js "></script>
  <script  type="text / javascript ">
     $(function(){
       var tbody = "";
    
     //------------遍历List集合 .each的使用-------------
      var obj =[{"name ":"项海军","password ":"123456 "},{"name ":"科比","password ":"333333 "}];
    $("#result ").html("遍历List集合.each的使用");
      alert(obj);//是个object元素
   //下面使用each进行遍历
   $.each(obj,function(n,value) { 
           alert(n+&#39; &#39;+value);
       var trs = "";
             trs += " < tr > <td > " +value.name+" < /td> <td>" + value.password +"</td > </tr>";
             tbody += trs;       
           });
         $("#project").append(tbody);
     
  });
  </script > </HEAD>
 
 <BODY>
       ------------此部分同1中的body部分--------------------
 </BODY >
</HTML>

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