JS / jQuery traverses JSON objects, JSON arrays, JSON array strings, and JSON object strings

JSON object

var jsonObj = {
"id": 102,
"year": "2019-2020",
"label": "2019-2020"
};

JS Traversal methods

for(var p in jsonObj){
alert(jsonObj[p]);
}

Jquery Traversal methods

$.each(jsonObj,function(index,value){
alert(value);
});

obtain json Object properties

alert("json："+jsonObj.year);

Traverse JSON Object string first converts the string to JSON object , The following traversal methods and traversal JSON The objects are the same .

JSON The object string is as follows ：

var jsonObjStr="{"id": 102,"year": "2019-2020","label": "2019-2020"}";

JSON Object string convert to JSON object

var jsonObj = JSON.parse(jsonObjStr);

Traversal method and JS Traverse JSON The object traversal method is the same , No more details here .

JSON Array

var jsonArr = [
{
"id": 102,
"year": "2019-2020",
"label": "2019-2020"
},
{
"id": 82,
"year": "2018-2019",
"label": "2018-2019"
},
{
"id": 42,
"year": "2017-2018",
"label": "2017-2018"
}];

Traversal methods

for(var i=0,l=jsonArr.length;i<l;i++){
for(var key in jsonArr[i]){
alert(key+':'+jsonArr[i][key]);
}
}
$.each(jsonArr,function(index,value){
alert(value.year);
});

Traverse JSON Array string first converts the string to JSON Array objects , The following traversal methods and traversal JSON Same as array object .

JSON Array string

var jsonArrStr="[{"id": 102,"year": "2019-2020","label": "2019-2020"},{"id": 82,"year": "2018-2019","label": "2018-2019"},{"id": 42,"year": "2017-2018","label": "2017-2018"}]";

JSON Array string convert to JSON Array

var jsonArr = $.parseJSON(jsonArrStr);