JSFiddle - React, Tailwind, and code Playground

HTML

<input id="year" type="number" placeholder="year" min="0" step="1" />
<br />Mother's day:
<output id="mday"></output>

JavaScript

function getMothersDay (year) {
    var date = new Date(year, 4, 7);
    date.setDate(7 + (7 - date.getDay()));
    return date;
}

var year = document.getElementById('year');
var mday = document.getElementById('mday');

year.oninput = function () {
    var date = getMothersDay(this.value);
    date = "May " + date.getDate() + ", " + this.value;
    mday.value = date;
};

year.value = new Date().getFullYear();
year.oninput();