Java Script Basics 

[1] Calling a function of another file from your javascript file

file 01:  graphinventor.js
=================

 console.log("-----------------------------------------Time Unit ");
 console.log("Previous Time Stamp ");


var test123 = function (data){
console.log("-----------------------------------------inside test123 ");
console.log(data)
alert("This is an alert" +data);

}

[3] https://datatables.net/manual/ajax

file 02: gadgetconf.js
===============

processData: function(data) {

console.log('data '+JSON.stringify(data));
 // in console of the browser (Ctrl+c) you see the content now as json data

console.log("------------------------");
test123(data);
console.log("------------------------");

}

main.js file (Loading graphinventor.js file first)
==========

       <!-- Custom -->
          <script src="js/graphinventor.js"></script>
          <script src="js/gadgetconf.js"></script>
          <script src="js/main.js"></script>

[2] Callback function is a function passed into another function.