JSFiddle - React, Tailwind, and code Playground

by evgeniel

HTML

<form>
<input id="from" type="date"> - <input id="to" type="date">
</form>
<form>
<input id="from" type="date"> - <input id="to" type="date">
</form>

JavaScript

var inputs = document.getElementsByTagName('input');
var from = document.getElementById('from');
var to = document.getElementById('to');

for(var i=0; i<inputs.length; i++) {
	inputs[i].addEventListener("change", function() {
  	if(from.value && to.value) {
    	var date_from = new Date(from.value.valueOf());
			var date_to = new Date(to.value.valueOf());
    	
      if(date_from > date_to) {
      	alert('Первый больше')
      }
    }
	}, false);
}