JavaScript Object traversal

first, the object is an array:  var arr = [{"id": "1", "TagName": "Apple"},{"id": "2", "TagName": "Orange"},{"id": "3", "TagName": "Banana"},{"id": "4", " TagName ":" Watermelon "},{" id ":" 5 "," TagName ":" Pineapple "}]; $.each (arr, function (index, obj) {

alert (index);              = = 0,1, 2, 3, 4 alert (obj);           =>{"id": "1", "TagName": "Apple"},{"id": "2", "TagName": "Orange"}...alert (obj.id);     = 1, 2, 3, 4, 5alert (Obj.tagname); + Apple, orange, banana, watermelon, pineapple

}); $.each (arr, function (index, obj) {alert (TagName of "+ Index +" is "+obj.tagname");

}); the tagname of the No. 0 item is Apple The tagname of the c8> 1th is orange ...... .....

=============================================================================================================== ============ Vararr = [9, 8,  7, 6 , 5 , 4 , 3 , 2 , 1 ];  Each traversal:$.each (Arr,function (index,value) {

alert ( index )}) =>0 1 2 3 4 5 6 7 8

$.each (Arr,function (index,value) {

alert ( value )

}) =>9 8 7 6 5 4 3 2 1 $.each (Arr,function () {

alert ( this )

}) =>9 8 7 6 5 4 3 2 1---------------------------------------------------- ------------------------------------------------------------------------------------For traversal:for  (Var i in arr)  {               //Not recommended for in traversal array       console.log (Arr[i]);   }          &NB Sp                          ,         &NB Sp           &NBSP;=&GT;9 8 7 6 5  4 3 2 1       for  (var i& nbsp;= 0; i < arr.length; i++)  {    console.log (Arr[i]);    }                                                              =>9 8 7 6 5  4 3 2 1    &nbsp ;                           ===================================== ======================================================================================  

vardata=[{"1":{"name":"kc","status":1}},{"2":{"name":"bc","status":2}}];  native JS gets:

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

     for ( var item  in data[i]){ //{"1":{"name":"kc","status":1}},{"2":{"name":"bc","status":2}}

         console.log( item ); // key     1,2

         console.log(data[i][item]); // value      {name: "kc", status: 1},{name: "bc", status: 2}

         console.log(data[i][item].name); //KC BC Get property value

         console.log(data[i][item].status); //1 2    获取属性值

     }

}

--------------------------------------------------------------------------------------------------------------- -------------------------

jquery get

     $.each(data,function(key,val){

     console.log(key); //索引

     console.log(val); //{"1":{"name":"kc","status":1}},{"2":{"name":"bc","status":2}}

     $.each(val,  function (key1,val1) {    

         console.log(key1); //key  1,2

         console.log(val1); //value, {name: "kc", status: 1},{name: "bc", status: 2}

         console.log(val1.name); //属性值

     });

})

=============================================================================================================== =============================================================================================================== ======================== second, the object is JSON:  var json = {"Jim": "One", "Tom": "N", "Lilei": "13"};jquery Get$.each (JSON, function (key, value) {

alert (key);               =>jim Tom Lilei Alert (value); =>11

});Native JS GetFor (var i in JSON) {alert (i); =>jim Tom Lilei    Alert (Json[i]); =>11 12 13};
=============================================================================================================== =============================================================================================================== ======================== Three, JSON is a string:(Solution: A JSON string is converted to a JavaScript object.) var json = ' [{' id ': ' 1 ', ' tagName ': ' Apple '},{' id ': ' 2 ', ' tagName ': ' Orange '},{' id ': ' 3 ', ' tagName ': ' Banana '},{' id ': ' 4 ', "TagName": "Watermelon"},{"id": "5", "TagName": "Pineapple"}] '; $.each ($.parsejson (JSON), function (idx, obj) {// $.parsejson (JSON)or json.parse (JSON)convert it to a JavaScript object string goto JSON objectalert (obj.tagname);            =>apple, orange, banana, watermelon, pineapple});

the parsing method of JSON  

There are two ways to parse JSON: eval () and Json.parse (), using the following methods:

var jsondata = ' {' data1 ': "Hello", "data2": "World"} '; var evaljson=eval ("(" +jsondata+ ")");             //Object {data1: "Hello", data2: "World"} var jsonparsejson=json.parse (Jsondata); Object {data1: "Hello", data2: "World"}

This converts the Jsondata JSON-formatted string into a JSON object.

 var dataobj=eval ("(" +data+ ")");//Convert to JSON objectEval Executes the code in the string when parsing a string (the consequences are pretty bad)
var obj= [{"id": "1", "TagName": "Apple"},{"id": "2", "TagName": "Orange"},{"id": "3", "TagName": "Banana"},{"id": "4", " TagName ":" Watermelon "},{" id ":" 5 "," TagName ":" Pineapple "}]; Json.stringify (obj)// JSON Object Turn string and Json.parse () instead  "[{"id": "1", "TagName": "Apple"},{"id": "2", "TagName": "Orange"},{"id": "3", "TagName": "Banana"},{"id": "4", " TagName ":" Watermelon "},{" id ":" 5 "," TagName ":" Pineapple "}]"

JavaScript Object traversal