JSON with Ajax

Sending JSON request payload and recieving JSON response object is very common tasks while dealing with AJAX and remote REST APIs.

JSON in request payload

var data = {"name" : "Lokesh"};

var xmlhttp = new XMLHttpRequest();

xmlhttp.open("POST", "/demo", true);

xmlhttp.send( JSON.stringify( data ) );

JSON in response body

var xmlhttp = new XMLHttpRequest();

xmlhttp.onreadystatechange = function() 
{
    if (this.readyState == 4 && this.status == 200) 
    {
    	//Use parse() method to convert JSON string to JSON object
        var responseJsonObj = JSON.parse(this.responseText);

        console.log( responseJsonObj.name );
        console.log( responseJsonObj.age );
    }
};

xmlhttp.open("GET", "/demo", true);

xmlhttp.send();