JSFiddle - React, Tailwind, and code Playground

HTML

<input type="text" name="begin[]" class='inputveld'>
 <input type="text" name="eind[]" class='inputveld' >
 <input type="text" name="begin[]" class='inputveld'>
 <input type="text" name="eind[]" class='inputveld' >
<div id="div_test" style="border:solid 1px black;height:50px;width:100%">
</div>

JavaScript

$("input[name='eind[]']").change(function(){
 
    var beg = $("input[name='begin[]']").val();
    var ein = $("input[name='eind[]']").val();
   
    var totaal = parseInt(ein) - parseInt(beg);
 
    $('div#div_test').text( "Totaal: " + totaal);
  
 });