JSFiddle - React, Tailwind, and code Playground

HTML

<nav>
    <input type="button" id="JAN" value="JAN" />
    <input type="button" id="FEB" value="FEB" />
    <input type="button" id="MAR" value="MAR" />
    <input type="button" id="APR" value="APR" />
    <input type="button" id="MAY" value="MAY" />
    <input type="button" id="JUN" value="JUN" />
    <input type="button" id="JUL" value="JUL" />
    <input type="button" id="AUG" value="AUG" />
    <input type="button" id="SEP" value="SEP" />
    <input type="button" id="OCT" value="OCT" />
    <input type="button" id="NOV" value="NOV" />
    <input type="button" id="DEC" value="DEC" />
</nav>

JavaScript

$(function () {

    function navbarMONTH(arg) {
        var datas = JSON.parse(arg);

        var dico = {
            "JAN": "01",   "FEB": "02",   "MAR": "03",
            "APR": "04",   "MAY": "05",   "JUN": "06",
            "JUL": "07",   "AUG": "08",   "SEP": "09",
            "OCT": "10",   "NOV": "11",   "DEC": "12",
        };

        var allButtons = document.querySelectorAll("nav input");
        for (var i = 0; i < allButtons.length; i++) {
            allButtons[i].onclick = function() {
                chargeCal(dico[this.id], datas.year);
            };
        }
    }

    navbarMONTH('{ "year": 2015 }');
});

function chargeCal(month, year) {
    console.log(month, year);
}