JSFiddle - React, Tailwind, and code Playground

HTML

Date: <input type="text" id="visitdate" value="23/03/2014">
<span id="errMsg"></span>

JavaScript

function checkDate() {
    if ($('#visitdate').length > 0) {
            var dateParts = $('#visitdate').val().split('/');
            var check = new Date(dateParts[2], dateParts[0],dateParts[1],0,0,0,0).getTime();
            var today = new Date().getTime(); 
            if (check < today) 
               $("#errMsg").html("Please enter a future date");
            else
               $("#errMsg").html(" ");
        }   
}

checkDate();

$("#visitdate").change(function() {
    checkDate();
});