JSON Basic JS Operation JSON Summary

JSON (JavaScript Object Notation) is a lightweight data interchange format that is ideal for data interchange formats in a completely language-independent text format. At the same time, JSON is a native JavaScript format, which means that working with JSON data in JavaScript does not require any special APIs or toolkits.

This article is mainly to the JS operation JSON Essentials to do a summary.

In JSON, there are two kinds of structures: objects and arrays.

1. An object starts with "{" (opening parenthesis) and "}" (the closing parenthesis) ends. Each "name" is followed by a ":" (colon); "' Name/value ' pairs" are separated by "," (comma). The name is enclosed in quotation marks, and if the value is a string, it must be in parentheses, and the numeric type is not required. For example:

var o={"Xlid": "Cxh", "Xldigitid": 123456, "Topscore": $, "topplaytime": "2009-08-20"};

2. An array is an ordered collection of values (value). An array begins with "[" (the left square bracket), and "]" (the right square bracket) ends. Use "," (comma) to separate values.

For example:

var jsonranklist=[{"Xlid": "Cxh", "Xldigitid": 123456, "Topscore": $, "topplaytime": "2009-08-20"},{"Xlid": "Zd", " Xldigitid ": 123456," Topscore ":" Topplaytime ":" 2009-11-20 "}];

To facilitate the processing of JSON data, JSON provides the Json.js package:

In the data transfer process, JSON is passed in the form of text, which is a string, and JS operates on a JSON object, so the conversion between the JSON object and the JSON string is key. For example:

JSON string:

var str1 = ' {' name ': ' cxh ', ' sex ': ' Man '} ';

JSON object:

var str2 = {"Name": "Cxh", "Sex": "Man"};

One, JSON string converted to JSON object

To use the above str1, you must use the following to turn the lead into a JSON object:

Convert from JSON string to JSON object

var obj = eval (' (' + str + ') ');

var obj = Str.parsejson (); Converted from a JSON string to a JSON object var obj = json.parse (str); Convert from JSON string to JSON object

Then, you can read this:

Alert (Obj.name); Alert (Obj.sex);

Special attention: If obj is originally a JSON object, then the use of the Eval () function after conversion (even if multiple conversions) is a JSON object, but the use of the Parsejson () function will be problematic (throwing a syntax exception).

Second, you can use toJSONString () or Global Essentials json.stringify () to convert the JSON object into a JSON string.

For example:

var last=obj.tojsonstring (); Converts the JSON object to the JSON character var last=json.stringify (obj); Converts a JSON object to a JSON character, alert (last);

Pay attention:

In the above multiple essentials, in addition to the eval () function is JS comes from, the other main points are from the Json.js package. The new version of JSON modifies the API to inject json.stringify () and Json.parse () Two essentials into the Javascript built-in object, which becomes the object.tojsonstring (), and the latter becomes the Strin G.parsejson (). If you are prompted not to find the tojsonstring () and Parsejson () Essentials, your JSON package version is too low.

JSON Basic JS Operation JSON Summary