JSFiddle - React, Tailwind, and code Playground

by JonNorman

HTML

start:<input type="text" id="st" value="01:00"><br>
end:<input type="text" id="et" value="12:00"><br>

JavaScript

$(document).ready(function() {
       $('#st, #et').change(function(){
         var sd = Date.parse("01/01/01 "+$('#st').val());
         var ed = Date.parse("01/01/01 "+$('#et').val());
         if(isNaN(sd)){
             alert('end time not a time');
         }else if(isNaN(ed)){
             alert('end time not a time');
         }else if(sd>=ed){
             alert('end time always greater then start time');
         }
     });
 });