Forse questo potrebbe interessarti:

codice:
<HTML>
<HEAD>
	<TITLE>Selezione da una lista digitando i caratteri in un TextBox</TITLE>
<HEAD>
<SCRIPT>
<!--
function Cerca()
	{
	with (document.modulo)
		{
		ThisFind=-1;
		StringToSearch=input.value;
		StringToSearchLength=StringToSearch.length;
		if (StringToSearchLength>0)
			for (i=0;i<stati.options.length;i++)
				ThisFind==-1&&stati.options[i].text.toLowerCase().substring(0,StringToSearchLength)==StringToSearch?ThisFind=i:null;
		else
			ThisFind=0;

		stati.selectedIndex=ThisFind;
		} 
	}
//-->
</SCRIPT>
</HEAD>
<BODY BGCOLOR="#ffffff">
<FORM NAME="modulo">
<INPUT TYPE="text" NAME="input" VALUE="Scrivi..." CLASS="" onKeyUp="this.value=this.value.toLowerCase();Cerca()" onFocus="this.select()"> 

<SELECT NAME="stati" size="5">
<OPTION>Albania</OPTION>
<OPTION>Algeria</OPTION>
<OPTION>American Samoa</OPTION>
<OPTION>Andorra</OPTION>
<OPTION>Angola</OPTION>
<OPTION>Anguilla</OPTION>
<OPTION>Antarctica</OPTION>
<OPTION>Antigua and Barbuda</OPTION>
<OPTION>Argentina</OPTION>
<OPTION>Armenia</OPTION>
<OPTION>Aruba</OPTION>
<OPTION>Australia</OPTION>
<OPTION>Austria</OPTION>
<OPTION>Azerbaidjan</OPTION>
<OPTION>Bahamas</OPTION>
<OPTION>Bahrain</OPTION>
<OPTION>Banglades</OPTION>
<OPTION>Barbados</OPTION>
<OPTION>Belarus</OPTION>
<OPTION>Belgium</OPTION>
<OPTION>Belize</OPTION>
<OPTION>Benin</OPTION>
<OPTION>Bermuda</OPTION>
<OPTION>Bolivia</OPTION>
<OPTION>Bosnia-Herzegovina</OPTION>
<OPTION>Botswana</OPTION>
<OPTION>Bouvet Island</OPTION>
<OPTION>Brazil</OPTION>
<OPTION>British Indian O. Terr.</OPTION>
<OPTION>Brunei Darussalam</OPTION>
<OPTION>Bulgaria</OPTION>
<OPTION>Burkina Faso</OPTION>
<OPTION>Burundi</OPTION>
<OPTION>Buthan</OPTION>
<OPTION>Cambodia</OPTION>
<OPTION>Cameroon</OPTION>
<OPTION>Canada</OPTION>
<OPTION>Cape Verde</OPTION>
<OPTION>Cayman Islands</OPTION>
<OPTION>Central African Rep.</OPTION>
<OPTION>Chad</OPTION>
<OPTION>Chile</OPTION>
<OPTION>China</OPTION>
<OPTION>Christmas Island</OPTION>
<OPTION>Cocos (Keeling) Isl.</OPTION>
<OPTION>Colombia</OPTION>
<OPTION>Comoros</OPTION>
<OPTION>Congo</OPTION>
<OPTION>Cook Islands</OPTION>
<OPTION>Costa Rica</OPTION>
<OPTION>Croatia</OPTION>
<OPTION>Cuba</OPTION>
<OPTION>Cyprus</OPTION>
<OPTION>Czech Republic</OPTION>
<OPTION>Czechoslovakia</OPTION>
<OPTION>Denmark</OPTION>
<OPTION>Djibouti</OPTION>
<OPTION>Dominica</OPTION>
<OPTION>Dominican Republic</OPTION>
<OPTION>East Timor</OPTION>
<OPTION>Ecuador</OPTION>
<OPTION>Egypt</OPTION>
<OPTION>El Salvador</OPTION>
<OPTION>Equatorial Guinea</OPTION>
<OPTION>Estonia</OPTION>
<OPTION>Ethiopia</OPTION>
<OPTION>Falkland Isl.(Malvinas)</OPTION>
<OPTION>Faroe Islands</OPTION>
<OPTION>Fiji</OPTION>
<OPTION>Finland</OPTION>
<OPTION>France</OPTION>
<OPTION>France (European Ter.)</OPTION>
<OPTION>French Southern Terr.</OPTION>
<OPTION>Gabon</OPTION>
<OPTION>Gambia</OPTION>
<OPTION>Georgia</OPTION>
<OPTION>Germany</OPTION>
<OPTION>Ghana</OPTION>
<OPTION>Gibraltar</OPTION>
<OPTION>Great Britain (UK)</OPTION>
<OPTION>Greece</OPTION>
<OPTION>Greenland</OPTION>
<OPTION>Grenada</OPTION>
<OPTION>Guadeloupe (Fr.)</OPTION>
<OPTION>Guam (US)</OPTION>
<OPTION>Guatemala</OPTION>
<OPTION>Guinea</OPTION>
<OPTION>Guinea Bissau</OPTION>
<OPTION>Guyana</OPTION>
<OPTION>Guyana (Fr.)</OPTION>
<OPTION>Haiti</OPTION>
<OPTION>Heard & McDonald Isl.</OPTION>
<OPTION>Honduras</OPTION>
<OPTION>Hong Kong</OPTION>
<OPTION>Hungary</OPTION>
<OPTION>Iceland</OPTION>
<OPTION>India</OPTION>
<OPTION>Indonesia</OPTION>
<OPTION>Iran</OPTION>
<OPTION>Iraq</OPTION>
<OPTION>Ireland</OPTION>
<OPTION>Israel</OPTION>
<OPTION>Italy</OPTION>
<OPTION>Ivory Coast</OPTION>
<OPTION>Jamaica</OPTION>
<OPTION>Japan</OPTION>
<OPTION>Jordan</OPTION>
<OPTION>Kazachstan</OPTION>
<OPTION>Kenya</OPTION>
<OPTION>Kirgistan</OPTION>
<OPTION>Kiribati</OPTION>
<OPTION>Korea (North)</OPTION>
<OPTION>Korea (South)</OPTION>
<OPTION>Kuwait</OPTION>
<OPTION>Laos</OPTION>
<OPTION>Latvia</OPTION>
<OPTION>Lebanon</OPTION>
<OPTION>Lesotho</OPTION>
<OPTION>Liberia</OPTION>
<OPTION>Libya</OPTION>
<OPTION>Liechtenstein</OPTION>
<OPTION>Lithuania</OPTION>
<OPTION>Luxembourg</OPTION>
<OPTION>Macau</OPTION>
<OPTION>Madagascar</OPTION>
<OPTION>Malawi</OPTION>
<OPTION>Malaysia</OPTION>
<OPTION>Maldives</OPTION>
<OPTION>Mali</OPTION>
<OPTION>Malta</OPTION>
<OPTION>Marshall Islands</OPTION>
<OPTION>Martinique (Fr.)</OPTION>
<OPTION>Mauritania</OPTION>
<OPTION>Mauritius</OPTION>
<OPTION>Mexico</OPTION>
<OPTION>Micronesia</OPTION>
<OPTION>Moldavia</OPTION>
<OPTION>Monaco</OPTION>
<OPTION>Mongolia</OPTION>
<OPTION>Montserrat</OPTION>
<OPTION>Morocco</OPTION>
<OPTION>Mozambique</OPTION>
<OPTION>Myanmar</OPTION>
<OPTION>Namibia</OPTION>
<OPTION>Nauru</OPTION>
<OPTION>Nepal</OPTION>
<OPTION>Netherland Antilles</OPTION>
<OPTION>Netherlands</OPTION>
<OPTION>Neutral Zone</OPTION>
<OPTION>New Caledonia (Fr.)</OPTION>
<OPTION>New Zealand</OPTION>
<OPTION>Nicaragua</OPTION>
<OPTION>Niger</OPTION>
<OPTION>Nigeria</OPTION>
<OPTION>Niue</OPTION>
<OPTION>Norfolk Island</OPTION>
<OPTION>Northern Mariana Isl.</OPTION>
<OPTION>Norway</OPTION>
<OPTION>Oman</OPTION>
<OPTION>Pakistan</OPTION>
<OPTION>Palau</OPTION>
<OPTION>Panama</OPTION>
<OPTION>Papua New</OPTION>
<OPTION>Paraguay</OPTION>
<OPTION>Peru</OPTION>
<OPTION>Philippines</OPTION>
<OPTION>Pitcairn</OPTION>
<OPTION>Poland</OPTION>
<OPTION>Polynesia (Fr.)</OPTION>
<OPTION>Portugal</OPTION>
<OPTION>Puerto Rico (US)</OPTION>
<OPTION>Qatar</OPTION>
<OPTION>Reunion (Fr.)</OPTION>
<OPTION>Romania</OPTION>
<OPTION>Russian Federation</OPTION>
<OPTION>Rwanda</OPTION>
<OPTION>Saint Lucia</OPTION>
<OPTION>Samoa</OPTION>
<OPTION>San Marino</OPTION>
<OPTION>Saudi Arabia</OPTION>
<OPTION>Senegal</OPTION>
<OPTION>Seychelles</OPTION>
<OPTION>Sierra Leone</OPTION>
<OPTION>Singapore</OPTION>
<OPTION>Slovak Republic</OPTION>
<OPTION>Slovenia</OPTION>
<OPTION>Solomon Islands</OPTION>
<OPTION>Somalia</OPTION>
<OPTION>South Africa</OPTION>
<OPTION>Soviet Union</OPTION>
<OPTION>Spain</OPTION>
<OPTION>Sri Lanka</OPTION>
<OPTION>St. Helena</OPTION>
<OPTION>St. Pierre & Miquelon</OPTION>
<OPTION>St. Tome and Principe</OPTION>
<OPTION>St.Kitts Nevis Anguilla</OPTION>
<OPTION>St.Vincent & Grenadines</OPTION>
<OPTION>Sudan</OPTION>
<OPTION>Suriname</OPTION>
<OPTION>Svalbard & Jan Mayen Is</OPTION>
<OPTION>Swaziland</OPTION>
<OPTION>Sweden</OPTION>
<OPTION>Switzerland</OPTION>
<OPTION>Syria</OPTION>
<OPTION>Tadjikistan</OPTION>
<OPTION>Taiwan</OPTION>
<OPTION>Tanzania</OPTION>
<OPTION>Thailand</OPTION>
<OPTION>Togo</OPTION>
<OPTION>Tokelau</OPTION>
<OPTION>Tonga</OPTION>
<OPTION>Trinidad & Tobago</OPTION>
<OPTION>Tunisia</OPTION>
<OPTION>Turkey</OPTION>
<OPTION>Turkmenistan</OPTION>
<OPTION>Turks & Caicos Islands</OPTION>
<OPTION>Tuvalu</OPTION>
<OPTION>US Minor outlying Isl.</OPTION>
<OPTION>Uganda</OPTION>
<OPTION>Ukraine</OPTION>
<OPTION>United Arab Emirates</OPTION>
<OPTION>United Kingdom</OPTION>
<OPTION>United States</OPTION>
<OPTION>Uruguay</OPTION>
<OPTION>Uzbekistan</OPTION>
<OPTION>Vanuatu</OPTION>
<OPTION>Vatican City State</OPTION>
<OPTION>Venezuela</OPTION>
<OPTION>Vietnam</OPTION>
<OPTION>Virgin Islands (British)</OPTION>
<OPTION>Virgin Islands (US)</OPTION>
<OPTION>Wallis & Futuna Islands</OPTION>
<OPTION>Western Sahara</OPTION>
<OPTION>Yemen</OPTION>
<OPTION>Yugoslavia</OPTION>
<OPTION>Zaire</OPTION>
<OPTION>Zambia</OPTION>
<OPTION>Zimbabwe</OPTION>
</SELECT>
</FORM>
</BODY>
</HTML>