JSFiddle - React, Tailwind, and code Playground

HTML

Days: <span id="days"></span><br/>
Months: <span id="months"></span><br/>

JavaScript

var date = new Date("15-Oct-2012");
Array.range= function(a, b, step){
    var A= [];
    if(typeof a== 'number'){
        A[0]= a;
        step= step || 1;
        while(a+step<= b){
            A[A.length]= a+= step;
        }
    }
    else{
        var s= 'abcdefghijklmnopqrstuvwxyz';
        if(a=== a.toUpperCase()){
            b=b.toUpperCase();
            s= s.toUpperCase();
        }
        s= s.substring(s.indexOf(a), s.indexOf(b)+ 1);
        A= s.split('');        
    }
    return A;
}

var days = Array.range(1, date.getDate());
document.getElementById("days").innerText = days;
var months = Array.range(1, date.getMonth() + 1);
document.getElementById("months").innerText = months;