JSFiddle - React, Tailwind, and code Playground

HTML

Date: <input type="text" id="visitdate" value="2014-03-23" onkeyup="checkDate();">
<span id="errMsg"></span>

JavaScript

function checkDate() {
    if ($('#visitdate').length > 0) {
            var check = Date.parse($('#visitdate').val());
            var today = new Date().getTime(); 
            if (check < today) 
               $("#errMsg").html("Please enter a future date");
            else
               $("#errMsg").html(" ");
        }   
}