get json data from separate file

    var xhttp = new XMLHttpRequest();
    xhttp.onreadystatechange = function() {
        if (this.readyState == 4 && this.status == 200) {
           // Typical action to be performed when the document is ready:
           console.log(xhttp.responseText);
        }
    };
    xhttp.open("GET", "json.json", true);
    xhttp.send();