JSFiddle - React, Tailwind, and code Playground

HTML

<div id="changeText"></div>

JavaScript

var todaysdate = new Date();
    var dd = todaysdate.getDate();
    var mm = todaysdate.getMonth()+1; //January is 0!

    var yyyy = todaysdate.getFullYear();
    if(dd<10){
        dd='0'+dd;
    } 
    if(mm<10){
        mm='0'+mm;
    } 
    var todaysdate = dd+'/'+mm+'/'+yyyy;

    var weekadates = 
    ["17/04/2018", "30/04/2018",//April
    "14/05/2018",               //May
    "04/06/2018", "18/06/2018",//June
    "02/07/2018", "16/07/2018",//July
    ];

    var weekbdates = 
    ["23/04/2018",             //April
    "07/05/2018", "21/05/2018",//May
    "11/06/2018", "25/06/2018",//June
    "09/07/2018"               //July
    ];



   

    var a = weekadates.indexOf(todaysdate);
    var b = weekbdates.indexOf(todaysdate);


    if (a > -1) 
    {
        document.getElementById("changeText").innerHTML = "Week 1";
    } 
    else if (b > -1) 
    {
        document.getElementById("changeText").innerHTML = "Week 2"; 
    } else
    {
    	document.getElementById("changeText").innerHTML = "Holidays!";
    }