JSFiddle - React, Tailwind, and code Playground

by Ben Bankes

HTML

<input id="textbox" value="10"/>

JavaScript

borrowbook();

function borrowbook() {
    var today = new Date();
    var day = today.getDate();
    var input_day = document.getElementById("textbox").value;
    
    var returnDate = new Date();
    returnDate.setDate(day + parseInt(input_day));
    
    var returnDay = returnDate.getDate();
    var returnMonth = returnDate.getMonth() + 1;
    var returnYear = returnDate.getFullYear();

    var fulltime1 = returnDay + "-" + returnMonth + "-" + returnYear;

    alert ("Return Date is: " + fulltime1);
}