Want to do "autocomplete" for countries in a webform? Using the <datalist> tag, you can use this ...

index.html

<input list="countries" name="country" size="25" placeholder="country">

<datalist id="countries">
	<option value="Afghanistan">
	<option value="Åland Islands">
	<option value="Albania">
	<option value="Algeria">
	<option value="American Samoa">
	<option value="Andorra">
	<option value="Angola">
	<option value="Anguilla">
	<option value="Antarctica">
	<option value="Antigua & Barbuda">
	<option value="Argentina">
	<option value="Armenia">
	<option value="Aruba">
	<option value="Ascension Island">
	<option value="Australia">
	<option value="Austria">
	<option value="Azerbaijan">
	<option value="Bahamas">
	<option value="Bahrain">
	<option value="Bangladesh">
	<option value="Barbados">
	<option value="Belarus">
	<option value="Belgium">
	<option value="Belize">
	<option value="Benin">
	<option value="Bermuda">
	<option value="Bhutan">
	<option value="Bolivia">
	<option value="Bosnia & Herzegovina">
	<option value="Botswana">
	<option value="Brazil">
	<option value="British Indian Ocean Territory">
	<option value="British Virgin Islands">
	<option value="Brunei">
	<option value="Bulgaria">
	<option value="Burkina Faso">
	<option value="Burundi">
	<option value="Cambodia">
	<option value="Cameroon">
	<option value="Canada">
	<option value="Canary Islands">
	<option value="Cape Verde">
	<option value="Caribbean Netherlands">
	<option value="Cayman Islands">
	<option value="Central African Republic">
	<option value="Ceuta & Melilla">
	<option value="Chad">
	<option value="Chile">
	<option value="China">
	<option value="Christmas Island">
	<option value="Cocos (Keeling) Islands">
	<option value="Colombia">
	<option value="Comoros">
	<option value="Congo - Brazzaville">
	<option value="Congo - Kinshasa">
	<option value="Cook Islands">
	<option value="Costa Rica">
	<option value="Côte d’Ivoire">
	<option value="Croatia">
	<option value="Cuba">
	<option value="Curaçao">
	<option value="Cyprus">
	<option value="Czechia">
	<option value="Denmark">
	<option value="Diego Garcia">
	<option value="Djibouti">
	<option value="Dominica">
	<option value="Dominican Republic">
	<option value="Ecuador">
	<option value="Egypt">
	<option value="El Salvador">
	<option value="Equatorial Guinea">
	<option value="Eritrea">
	<option value="Estonia">
	<option value="Ethiopia">
	<option value="Eurozone">
	<option value="Falkland Islands">
	<option value="Faroe Islands">
	<option value="Fiji">
	<option value="Finland">
	<option value="France">
	<option value="French Guiana">
	<option value="French Polynesia">
	<option value="French Southern Territories">
	<option value="Gabon">
	<option value="Gambia">
	<option value="Georgia">
	<option value="Germany">
	<option value="Ghana">
	<option value="Gibraltar">
	<option value="Greece">
	<option value="Greenland">
	<option value="Grenada">
	<option value="Guadeloupe">
	<option value="Guam">
	<option value="Guatemala">
	<option value="Guernsey">
	<option value="Guinea">
	<option value="Guinea-Bissau">
	<option value="Guyana">
	<option value="Haiti">
	<option value="Honduras">
	<option value="Hong Kong SAR China">
	<option value="Hungary">
	<option value="Iceland">
	<option value="India">
	<option value="Indonesia">
	<option value="Iran">
	<option value="Iraq">
	<option value="Ireland">
	<option value="Isle of Man">
	<option value="Israel">
	<option value="Italy">
	<option value="Jamaica">
	<option value="Japan">
	<option value="Jersey">
	<option value="Jordan">
	<option value="Kazakhstan">
	<option value="Kenya">
	<option value="Kiribati">
	<option value="Kosovo">
	<option value="Kuwait">
	<option value="Kyrgyzstan">
	<option value="Laos">
	<option value="Latvia">
	<option value="Lebanon">
	<option value="Lesotho">
	<option value="Liberia">
	<option value="Libya">
	<option value="Liechtenstein">
	<option value="Lithuania">
	<option value="Luxembourg">
	<option value="Macau SAR China">
	<option value="Macedonia">
	<option value="Madagascar">
	<option value="Malawi">
	<option value="Malaysia">
	<option value="Maldives">
	<option value="Mali">
	<option value="Malta">
	<option value="Marshall Islands">
	<option value="Martinique">
	<option value="Mauritania">
	<option value="Mauritius">
	<option value="Mayotte">
	<option value="Mexico">
	<option value="Micronesia">
	<option value="Moldova">
	<option value="Monaco">
	<option value="Mongolia">
	<option value="Montenegro">
	<option value="Montserrat">
	<option value="Morocco">
	<option value="Mozambique">
	<option value="Myanmar (Burma)">
	<option value="Namibia">
	<option value="Nauru">
	<option value="Nepal">
	<option value="Netherlands">
	<option value="New Caledonia">
	<option value="New Zealand">
	<option value="Nicaragua">
	<option value="Niger">
	<option value="Nigeria">
	<option value="Niue">
	<option value="Norfolk Island">
	<option value="North Korea">
	<option value="Northern Mariana Islands">
	<option value="Norway">
	<option value="Oman">
	<option value="Pakistan">
	<option value="Palau">
	<option value="Palestinian Territories">
	<option value="Panama">
	<option value="Papua New Guinea">
	<option value="Paraguay">
	<option value="Peru">
	<option value="Philippines">
	<option value="Pitcairn Islands">
	<option value="Poland">
	<option value="Portugal">
	<option value="Puerto Rico">
	<option value="Qatar">
	<option value="Réunion">
	<option value="Romania">
	<option value="Russia">
	<option value="Rwanda">
	<option value="Samoa">
	<option value="San Marino">
	<option value="São Tomé & Príncipe">
	<option value="Saudi Arabia">
	<option value="Senegal">
	<option value="Serbia">
	<option value="Seychelles">
	<option value="Sierra Leone">
	<option value="Singapore">
	<option value="Sint Maarten">
	<option value="Slovakia">
	<option value="Slovenia">
	<option value="Solomon Islands">
	<option value="Somalia">
	<option value="South Africa">
	<option value="South Georgia & South Sandwich Islands">
	<option value="South Korea">
	<option value="South Sudan">
	<option value="Spain">
	<option value="Sri Lanka">
	<option value="St. Barthélemy">
	<option value="St. Helena">
	<option value="St. Kitts & Nevis">
	<option value="St. Lucia">
	<option value="St. Martin">
	<option value="St. Pierre & Miquelon">
	<option value="St. Vincent & Grenadines">
	<option value="Sudan">
	<option value="Suriname">
	<option value="Svalbard & Jan Mayen">
	<option value="Swaziland">
	<option value="Sweden">
	<option value="Switzerland">
	<option value="Syria">
	<option value="Taiwan">
	<option value="Tajikistan">
	<option value="Tanzania">
	<option value="Thailand">
	<option value="Timor-Leste">
	<option value="Togo">
	<option value="Tokelau">
	<option value="Tonga">
	<option value="Trinidad & Tobago">
	<option value="Tristan da Cunha">
	<option value="Tunisia">
	<option value="Turkey">
	<option value="Turkmenistan">
	<option value="Turks & Caicos Islands">
	<option value="Tuvalu">
	<option value="U.S. Outlying Islands">
	<option value="U.S. Virgin Islands">
	<option value="Uganda">
	<option value="Ukraine">
	<option value="United Arab Emirates">
	<option value="United Kingdom">
	<option value="United Nations">
	<option value="United States">
	<option value="Uruguay">
	<option value="Uzbekistan">
	<option value="Vanuatu">
	<option value="Vatican City">
	<option value="Venezuela">
	<option value="Vietnam">
	<option value="Wallis & Futuna">
	<option value="Western Sahara">
	<option value="Yemen">
	<option value="Zambia">
	<option value="Zimbabwe">
</datalist>