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Valeri Tandilashvili's JSON Notes
Results: 39
creating JSON file Step-by-Step from Scratch
JSON supported data types with examples
JSON Data Structures
JSON is built on 2 structures: 
Object
- a collection of key/value pairs 
Array
- an ordered list of values
JSON.stringify CODE
Creates JSON string from a JavaScript object
var obj = { name: "John", age: 30, city: "New York" };

// Converts object into JSON string
var myJSON = JSON.stringify(obj);

// Puts the string into element with id: demo
document.getElementById("demo").innerHTML = myJSON;
JSON.parse CODE 
JSON.parse()
Parses the data and converts it into a JavaScript object
let txt = '{"name":"John", "age":30, "city":"New York"}'

// Converts JSON string into a JavaScript object.
let obj = JSON.parse(txt);

// Puts the data into "p" element with id: demo
document.getElementById("demo").innerHTML = obj.name + ", " + obj.age;
JavaScript data types that JSON does not support 
- a function
- a date
- a symbol
- undefined
array in JSON
It is an ordered collection of values The values are separated by comma 
,
These are enclosed in square brackets 
[]
which means that array begins with 
[
and ends with 
]
{
   "books": [
      { "language":"Java" , "edition":"second" },
      { "language":"C++" , "lastName":"fifth" },
      { "language":"C" , "lastName":"third" }
   ]
}
JSON Basics 
JSON
stands for 
JavaScript Object Notation
JSON
is a way of communicating data with specific rules 
JSON
is a syntax for storing and exchanging data 
JSON
is text, written with JavaScript object notation The syntax is taken from 
JavaScript
but 
JSON
is portable with other languages 
JSON
is a lightweight data-interchange format It's easy for humans to read and write It's easy for machines to parse and generate A common use of JSON is to exchange data 
to/from
a web server 
application/json
is the official Internet media type for 
JSON
.json
is the 
JSON
filename extension
JSON - dynamically change HTML table content CODE 
Dynamically
changes HTML table content using XMLHttpRequest after choosing any option on 
<select>
obj = { table: "customers", limit: 20 };
dbParam = JSON.stringify(obj);
xmlhttp = new XMLHttpRequest();
xmlhttp.onreadystatechange = function() {
  if (this.readyState == 4 && this.status == 200) {
    myObj = JSON.parse(this.responseText);
    txt += "<table border='1'>"
    for (x in myObj) {
      txt += "<tr><td>" + myObj[x].name + "</td></tr>";
    }
    txt += "</table>"
    document.getElementById("demo").innerHTML = txt;
  }
}
xmlhttp.open("POST", "json_demo_db_post.php", true);
xmlhttp.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
xmlhttp.send("x=" + dbParam);
Results: 39