JSFiddle - React, Tailwind, and code Playground

HTML

<select id="dayOfTheWeek" name="dayOfTheWeek"></select>

JavaScript

function populateDays() {
var days = [ "Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday" ];
var dayOfWeek = document.getElementById("dayOfTheWeek");
var today = (new Date()).getDay();

for (var i = 0; i < days.length; i++) {
    var length = dayOfWeek.options.length;
    dayOfWeek.add(new Option(days[i], i), length);
}
dayOfWeek.selectedIndex = today;
}

populateDays();