JSFiddle - React, Tailwind, and code Playground

HTML

<div>
	<div>
		<select id="countrylist" style="width: 150px;">
		    <option value="1">India</option>
		    <option value="2">Australia</option>
		    <option value="3">London</option>
		    <option value="4">Switzerland</option>
		    <option value="5">Argentina</option>
		    <option value="6">Bhutan</option>
		    <option value="7">Canada</option>
		</select>
		<input type="button" id="btnDelete" value="Delete" />
	</div>

		<div id='additem'>
		    <input type='text' name='addcountry' id="readme"/>
		    <button class="addoption">Add Country</button>
		</div>
</div>

JavaScript

$(function () {
        $("#btnDelete").bind("click", function () {
        	// on click of delete button the selected option will be removed
            $("#countrylist option:selected").remove();
        });
      });

     // on click of add button
    $('.addoption').click(function(){
    	// the value of input will be stored in a variable
        var item = $('input[name=addcountry]').val();
        // the value of input will be appended in select option
        $('#countrylist').append('<option>'+ item +' </option>');
    });