callback2.js

firstFunctionCall : find([1,2], function(results) {
    process(results, onMethodsDone);
});

callBackFunctionForProcess : function onMethodsDone(results1) {
    alert("Results : "+results1);
}

alert("meanwhile I show up");

function process(elements, callback1) {
    //The time consuming operation
        setTimeout(function() {
            elements.push(6,7,8);
            callback1(elements);
        }, 2000)
    }

function find(elements, callback) {
    //The time consuming operation
    setTimeout(function() {
        elements.push(3,4,5);
        callback(elements);
    } ,2000);
}