JSON-Common conversions

Simply record the use of the Json.parse () and json.stringify () functions in jquery, and the eval () function in JS

1,json.parse function (Common)

Function: Converts a JavaScript object notation (JSON) string to an object.

Grammar:JSON.parse(text [reviver])

Parameters:

• text required. a valid JSON string.
• Reviver Optional. a function that transforms the result. This function is called for each member of the object.

Return value: An object or an array

Example:

var json = ' {' name ': ' YZ ', ' age ': ' University ': ' Sjzxy '} '; var info = json.parse (JSON); Resolves to a JSON object document.write (Info.name + ' is a student of ' + info. University + ' and he is ' + Info.age + "Years"); /info to Object

2,json.stringify () function

Role: Converts JavaScript values to JavaScript Object Notation (JSON) strings

Syntax: json.stringify (value [, Replacer] [, space])

Parameters:

• Value required, typically a JavaScript value (usually an object or an array) that needs to be converted
• Replacer optional, function or array for converting results
• Space is optional. adds indents, spaces, and line breaks to the return value JSON text to make it easier to read.

Return value: A string containing JSON text

Example

var info = {Name: "YZ", age:22,university: "Sjzxy"}; var json = json.stringify (info); Convert to JSON string
document.write (JSON); Output is {"name": "GDT", "Age": "University": "Gdut"}

(3) eval () function

Function: the eval () function computes a string and executes the JavaScript code in it.

Syntax:eval (String)

Parameters:

• String required to be evaluated, containing the JAVASCRIPT expression to be evaluated or the statement to be executed.

Return value: Returns the value of the computed string, if any (no change is returned)

Example

Eval ("X=11;y=2;document.write (X*y)");  Output is document.write (eval ("+ +)"); Output is 4 var x=10;　　document.write (eval (x+17)); Output is 27

The format of the eval () parsing string

Alert (eval (' (' + ' (' + ') ' {} ') ') but Eval () is unsafe for easy execution of dangerous code inside
Example:

var str2 = ' {' A ': (function () {alert ("I can do something bad!");}) ()}‘;
Eval (' (' +str2+ ') ');  

The code that executes the danger is unsafe  but json.parse () completely overcomes this problem, so the actual use of less

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JSON-Common conversions