Edit in JSFiddle

var data = [];
for (var i = 0; i < 100; i = i + 5) {
    data.push(i);
}
displayArray(data);
$('#output').append('Lets start Parallel Processing' + dateOutput() + '<br/>');
async.map(data, processData, function (err,result) {
    if (err) {
        $('#output').append('OOPS! How is this possible?' + "<br/>");
    }

    $('#output').append('Parallel Processing Done At ' + dateOutput() + '<br/>');
    displayArray(result);
    $('#output').append('Lets Start Same Operation In Series ' +  dateOutput() + '<br/>');
    async.mapSeries(data, processData, function (err,result) {
        if (err) {
            $('#output').append('OOPS! How is this possible?' + "<br/>");
        }
        $('#output').append('Series Processing Done At ' + dateOutput() + '<br/>');
        displayArray(result);
        $('#output').append('Lets Start Same Operation In Series But With 5 at time ' + dateOutput() +'<br/>');
        async.mapLimit(data, 5, processData, function (err,result) {
            if (err) {
                $('#output').append('OOPS! How is this possible?' + "<br/>");
            }
            $('#output').append('Series Processing Done ' + dateOutput() + '<br/>');
            displayArray(result);
        });
    });
});

function processData(item, callback) {
    //we are just diving the number by 5
    //but we can actually do a very long process here 
    setTimeout(function () {
        var new_item = (item / 5);
        callback(null, new_item); //no error
        //incase of error pass the error in callback function 
    }, 500);
}

function displayArray(to_display) {
    $('#output').append('Our Array<br/>');
    $('#output').append('====================<br/>');
    for (var i = 0; i < to_display.length; i++) {
        $('#output').append(to_display[i] + ",");
    }
    $('#output').append('<br/>' + '====================' + '<br/>');
}

function dateOutput() {
    var date = new Date();
    return date.getHours() + ":" + +date.getMinutes() + ":" + +date.getSeconds();
}