JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://davidstutz.github.io/bootstrap-multiselect/dist/js/bootstrap-multiselect.js"></script>
<link rel="stylesheet" href="https://davidstutz.github.io/bootstrap-multiselect/dist/css/bootstrap-multiselect.css">
<link rel="stylesheet" href="https://davidstutz.github.io/bootstrap-multiselect/docs/css/bootstrap-3.3.2.min.css">
<script src="https://davidstutz.github.io/bootstrap-multiselect/docs/js/bootstrap-3.3.2.min.js"></script>
<input type="text" id="addRow"/>

<input type="button" id="btn" value="Add"/>
<form id="form1">

<div style="padding:20px">
<select id="chkveg" multiple="multiple">
</select><br /><br />

</div>

</form>

CSS

.multiselect-container>li>a>label {
  padding: 4px 20px 3px 20px;
}

JavaScript

$(document).ready(function() {
 $('#btn').click(function() {
        var val = $("#addRow").val();
        var htm = '';
     htm += '<option>'+val+'</option>';
        $('.multiselect-container').append(htm);
          $('#chkveg').append(htm);
    });
$('#chkveg').multiselect({

includeSelectAllOption: true

});

});