JSFiddle - React, Tailwind, and code Playground

HTML

<input type="button" id="btnasd"  value="Click" />

JavaScript

$(document).ready(function () {

    $("#btnasd").click(function () {
        var Idtype = $("#dropdownlist").val();
        var valuetype = $('#dropdownlist option:selected').text();
        $.post("/Role/displayRolevalue", { Id: $('#dropdownlist').val(), value: $('#dropdownlist option:selected').text() }, function (data) {
            $("#dropdownlist").html(data)
        })
    });
});