JSON (02) JSON parsing and Application in JQuery

When JQuery is used for frontend page interaction with background programs, JSON plays a major role in recording JQuery's related things.

Several functions related to JSON processing:
1. convert a string to a JSON object
A. JavaScript is converted using eval, but this method is not secure and is not recommended.
Var jsonObj =Eval(JsonStr );

B. JSON. parse mode, but ie6 and ie7 are not supported. You need to download a JS extension at http://www.json.org/js.html.
Var jsonObj =JSON. parse(JsonStr );

C. JQuery uses parseJSON functions to improve security
Var jsonObj =JQuery. parseJSON(JsonStr );

2. Convert the JSON object into a string
Var jsonStr =JSON. stringify(JsonObj );

3. getJSON (). This function obtains json data through the get request.
JQuery. getJSON (url, data, callback)
· Url is used to provide the address page of json data
Data (Optional) is a key-value pair that is sent to the server.
· Callback (Optional) callback function, the processing function after the json data request is successful
For details, refer:
Http://www.w3school.com.cn/jquery/ajax_getjson.asp
4. GET and. POST can both directly transmit or receive JSON strings.
....

JSON display:

Example 1.

[{"Ret": "c:/tmp/11gR2", "type": "DIR" },{ "ret": "c:/tmp/xcl. log "," type ":" FILE "},{" ret ":" c:/tmp/soft "," type ":" DIR "}]

The expanded view is as follows:

{"Name": "xcl. log", "type": "FILE", "fileversion ":[
{& Quot; version & quot;: 1, & quot; backupTime & quot;: 100, & quot; createtime & quot;: 80, & quot; modifytime & quot;: 70, & quot; size & quot;: & quot; 10 m & quot "},
{& Quot; version & quot;: 2, & quot; backupTime & quot;: 120, & quot; createtime & quot;: 50, & quot; modifytime & quot;: 80, & quot; size & quot;: & quot; 50 m & quot;}]}

Here is an example of JSON usage:

 JSON DEMO<Script src = "http://code.jquery.com/jquery-1.11.0.min.js"> </script> <script type = "text/javascript"> $ (document ). ready (function () {function demo1 () {// string var jsonStr = '[{"ret": "c:/tmp/11gR2", "type ": "DIR" },{ "ret": "c:/tmp/xcl. log "," type ":" FILE "},{" ret ":" c:/tmp/soft "," type ":" DIR "}] '; // convert a string to a JSON object // JavaScript is converted using eval, but this method is not safe and is not recommended. // Var jsonObj = eval (jsonStr); // JSON. parse mode, but ie6 and ie7 are not supported. You need to download a JS extension at http://www.json.org/js.html. Var jsonObj = JSON. parse (jsonStr); // JQuery uses the parseJSON function to improve the security of var jsonObj = jQuery. parseJSON (jsonStr); // use each to traverse the JSON array var info = "length =" + jsonObj. length; $. each (jsonObj, function (n, value) {info + ="
"+ Value. type + ':' + value. ret}); ('{jsoninfo_div'{.html (info);} function demo2 () {// directly assign a complex JSON to the JS variable var jsonObj = {"name": "xcl. log "," type ":" FILE "," fileversion ": [{" version ": 1," backupTime ": 100," createtime ": 80," modifytime ": 70, "size": "10 m" },{ "version": 2, "backupTime": 120, "createtime": 50, "modifytime": 80, "size": "50 m"}]} var info = "name =" + jsonObj. name; info + ="
"+" Length = "+ jsonObj. fileversion. length; $. each (jsonObj. fileversion, function (n, value) {info + ="
Version: "+ jsonObj. fileversion [n]. version + ': size:' + jsonObj. fileversion [n]. size;}); ('{jsoninfo2_div'{.html (info); ('{jsondemo21_div'{.html (JSON. stringify (jsonObj);} demo1 (); demo2 () ;}); </script>JSON DEMO
Demo1:

Demo2:

Effect:

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