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

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

        includeSelectAllOption: true

    });

});