JSFiddle - React, Tailwind, and code Playground

HTML

<div id="countriesMore" class="tboxContent" style="display: block;">
                        <h1 class="NoLeftMargin">Select which countries you are travelling to</h1>
                        <fieldset>
                            <legend>Select which countries you are travelling to</legend>
                            <div id="countrySearchInputWrap">
                                <input type="text" id="allCountryLiveSearch" class="form-control" placeholder="Search for a country">
                                <a href="#" class="ClearSearch"></a>
                            </div>
                            <div id="allCountriesWrap">
                                <div id="allCountriesListWrap" style="height: 2484px;">
                                    <div id="allCountriesList">
                                            <label data-country-code="1000">Abu Dhabi<span></span></label>
                                            <label data-country-code="1001">Afghanistan<span></span></label>
                                            <label data-country-code="1002">Alaska<span></span></label>
                                            <label data-country-code="1003">Albania<span></span></label>
                                            <label data-country-code="1004">Algeria<span></span></label>
                                            <label data-country-code="1005">Andorra<span></span></label>
                                            <label data-country-code="1006">Angola<span></span></label>
                                            <label data-country-code="1007">Anguilla<span></span></label>
                                            <label data-country-code="1008">Antarctic<span></span></label>
                                            <label data-country-code="1009">Antigua<span></span></label>
                                            <label data-country-code="1010">Argentina<span></span></label>
                                ...

JavaScript

$('#allCountryLiveSearch').on('keyup', function() {
    var query = this.value;

    $('#allCountriesList label').each(function(i, elem) {
          if (elem.value.indexOf(query) != -1) {
              elem.style.display = 'block';
          }else{
              elem.style.display = 'none';
          }
    });
});