he probado el código que he escrito a continuación (adoptada a partir del código) y funciona. ¿Tal vez se olvidó de incluir el javascript jquery para cada idioma? Solo he incluido tres idiomas (por ejemplo, francés) como ejemplo. También tengo el evento de cambio para la activación de la opción de selección en el idioma, en lugar de activarlo en onSelect.
También probé su versión de ponerlo en una función y eso funciona, excepto que debido a su activación en el seleccionar, es necesario seleccionar primero una fecha antes de que comience a funcionar, y luego un idioma después de eso.
Primera versión (en una función, funciona, pero un problema que no se muestra en un idioma hasta la fecha se ha seleccionado en primer lugar):
<html><head><title>Test1</title>
<script type="text/javascript" src="jquery-1.7.2.min.js"></script>
<link type="text/css" href="css/ui-lightness/jquery-ui-1.8.18.custom.css" rel="Stylesheet" />
<script type="text/javascript" src="js/jquery-ui-1.8.18.custom.min.js"></script>
<script type="text/javascript" src="jquery.ui.datepicker-fr.js"></script>
<script type="text/javascript" src="jquery.ui.datepicker-ar.js"></script>
<script type="text/javascript" src="jquery.ui.datepicker-af.js"></script>
<script type="text/javascript" src="jquery.ui.datepicker-en-GB.js"></script>
</head><body>
<script type="text/javascript">
$(function() {
$.datepicker.setDefaults($.datepicker.regional[ "" ]);
$("#from").datepicker({
defaultDate: "+4w",
changeMonth: true,
numberOfMonths: 3,
showButtonPanel: true,
showOn: "button",
minDate:"+1d",
dateFormat:"yy/mm/dd",
showAnim:"bounce",
onSelect: function(selectedDate) {
$("#from").datepicker($.datepicker.regional[ "en-GB" ]);
$("#locale").change(function() {
$("#from").datepicker("option",
$.datepicker.regional[ $(this).val() ]);
});
}
});
});
</script>
<p>Date: <input type="text" id="from"/>
<select id="locale">
<option value="af">Afrikaans</option>
<option value="sq">Albanian (Gjuha shqipe)</option>
<option value="ar-DZ">Algerian Arabic</option>
<option value="ar">Arabic (‫(لعربي</option>
<option value="hy">Armenian (Հայերեն)</option>
<option value="az">Azerbaijani (Azərbaycan dili)</option>
<option value="eu">Basque (Euskara)</option>
<option value="bs">Bosnian (Bosanski)</option>
<option value="bg">Bulgarian (български език)</option>
<option value="ca">Catalan (Català)</option>
<option value="zh-HK">Chinese Hong Kong (繁體中文)</option>
<option value="zh-CN">Chinese Simplified (简体中文)</option>
<option value="zh-TW">Chinese Traditional (繁體中文)</option>
<option value="hr">Croatian (Hrvatski jezik)</option>
<option value="cs">Czech (čeština)</option>
<option value="da">Danish (Dansk)</option>
<option value="nl-BE">Dutch (Belgium)</option>
<option value="nl">Dutch (Nederlands)</option>
<option value="en-AU">English/Australia</option>
<option value="en-NZ">English/New Zealand</option>
<option value="en-GB">English/UK</option>
<option value="eo">Esperanto</option>
<option value="et">Estonian (eesti keel)</option>
<option value="fo">Faroese (føroyskt)</option>
<option value="fa">Farsi/Persian (‫(فارسی</option>
<option value="fi">Finnish (suomi)</option>
<option value="fr" selected="selected">French (Français)</option>
<option value="fr-CH">French/Swiss (Français de Suisse)</option>
<option value="gl">Galician</option>
<option value="ge">Georgian</option>
<option value="de">German (Deutsch)</option>
<option value="el">Greek (Ελληνικά)</option>
<option value="he">Hebrew (‫(עברית</option>
<option value="hi">Hindi (हिंदी)</option>
<option value="hu">Hungarian (Magyar)</option>
<option value="is">Icelandic (Õslenska)</option>
<option value="id">Indonesian (Bahasa Indonesia)</option>
<option value="it">Italian (Italiano)</option>
<option value="ja">Japanese (日本語)</option>
<option value="kk">Kazakhstan (Kazakh)</option>
<option value="km">Khmer</option>
<option value="ko">Korean (한국어)</option>
<option value="lv">Latvian (Latvieöu Valoda)</option>
<option value="lt">Lithuanian (lietuviu kalba)</option>
<option value="lb">Luxembourgish</option>
<option value="mk">Macedonian</option>
<option value="ml">Malayalam</option>
<option value="ms">Malaysian (Bahasa Malaysia)</option>
<option value="no">Norwegian (Norsk)</option>
<option value="pl">Polish (Polski)</option>
<option value="pt">Portuguese (Português)</option>
<option value="pt-BR">Portuguese/Brazilian (Português)</option>
<option value="rm">Rhaeto-Romanic (Romansh)</option>
<option value="ro">Romanian (Română)</option>
<option value="ru">Russian (Русский)</option>
<option value="sr">Serbian (српски језик)</option>
<option value="sr-SR">Serbian (srpski jezik)</option>
<option value="sk">Slovak (Slovencina)</option>
<option value="sl">Slovenian (Slovenski Jezik)</option>
<option value="es">Spanish (Español)</option>
<option value="sv">Swedish (Svenska)</option>
<option value="ta">Tamil (தமிழ்)</option>
<option value="th">Thai (ภาษาไทย)</option>
<option value="tj">Tajikistan</option>
<option value="tr">Turkish (Türkçe)</option>
<option value="uk">Ukranian (Українська)</option>
<option value="vi">Vietnamese (Tiếng Việt)</option>
<option value="cy-GB">Welsh/UK (Cymraeg)</option>
</select></p>
</body></html>
Segunda versión (no en una función, también funciona, parece funcionar mejor para mí, ya que no tiene que seleccionar una fecha para que cambie de idioma):
<html><head><title>Test1</title>
<script type="text/javascript" src="jquery-1.7.2.min.js"></script>
<link type="text/css" href="css/ui-lightness/jquery-ui-1.8.18.custom.css" rel="Stylesheet" />
<script type="text/javascript" src="js/jquery-ui-1.8.18.custom.min.js"></script>
<script type="text/javascript" src="jquery.ui.datepicker-fr.js"></script>
<script type="text/javascript" src="jquery.ui.datepicker-ar.js"></script>
<script type="text/javascript" src="jquery.ui.datepicker-af.js"></script>
</head><body>
<script type="text/javascript">
$(function() {
$.datepicker.setDefaults($.datepicker.regional[ "" ]);
$("#from").datepicker({
defaultDate: "+4w",
changeMonth: true,
numberOfMonths: 3,
showButtonPanel: true,
showOn: "button",
minDate:"+1d",
dateFormat:"yy/mm/dd",
showAnim:"bounce"
});
$("#from").datepicker($.datepicker.regional[ "en-GB" ]);
$("#locale").change(function() {
$("#from").datepicker("option",
$.datepicker.regional[ $(this).val() ]);
});
});
</script>
<p>Date: <input type="text" id="from"/>
<select id="locale">
<option value="af">Afrikaans</option>
<option value="sq">Albanian (Gjuha shqipe)</option>
<option value="ar-DZ">Algerian Arabic</option>
<option value="ar">Arabic (‫(لعربي</option>
<option value="hy">Armenian (Հայերեն)</option>
<option value="az">Azerbaijani (Azərbaycan dili)</option>
<option value="eu">Basque (Euskara)</option>
<option value="bs">Bosnian (Bosanski)</option>
<option value="bg">Bulgarian (български език)</option>
<option value="ca">Catalan (Català)</option>
<option value="zh-HK">Chinese Hong Kong (繁體中文)</option>
<option value="zh-CN">Chinese Simplified (简体中文)</option>
<option value="zh-TW">Chinese Traditional (繁體中文)</option>
<option value="hr">Croatian (Hrvatski jezik)</option>
<option value="cs">Czech (čeština)</option>
<option value="da">Danish (Dansk)</option>
<option value="nl-BE">Dutch (Belgium)</option>
<option value="nl">Dutch (Nederlands)</option>
<option value="en-AU">English/Australia</option>
<option value="en-NZ">English/New Zealand</option>
<option value="en-GB">English/UK</option>
<option value="eo">Esperanto</option>
<option value="et">Estonian (eesti keel)</option>
<option value="fo">Faroese (føroyskt)</option>
<option value="fa">Farsi/Persian (‫(فارسی</option>
<option value="fi">Finnish (suomi)</option>
<option value="fr" selected="selected">French (Français)</option>
<option value="fr-CH">French/Swiss (Français de Suisse)</option>
<option value="gl">Galician</option>
<option value="ge">Georgian</option>
<option value="de">German (Deutsch)</option>
<option value="el">Greek (Ελληνικά)</option>
<option value="he">Hebrew (‫(עברית</option>
<option value="hi">Hindi (हिंदी)</option>
<option value="hu">Hungarian (Magyar)</option>
<option value="is">Icelandic (Õslenska)</option>
<option value="id">Indonesian (Bahasa Indonesia)</option>
<option value="it">Italian (Italiano)</option>
<option value="ja">Japanese (日本語)</option>
<option value="kk">Kazakhstan (Kazakh)</option>
<option value="km">Khmer</option>
<option value="ko">Korean (한국어)</option>
<option value="lv">Latvian (Latvieöu Valoda)</option>
<option value="lt">Lithuanian (lietuviu kalba)</option>
<option value="lb">Luxembourgish</option>
<option value="mk">Macedonian</option>
<option value="ml">Malayalam</option>
<option value="ms">Malaysian (Bahasa Malaysia)</option>
<option value="no">Norwegian (Norsk)</option>
<option value="pl">Polish (Polski)</option>
<option value="pt">Portuguese (Português)</option>
<option value="pt-BR">Portuguese/Brazilian (Português)</option>
<option value="rm">Rhaeto-Romanic (Romansh)</option>
<option value="ro">Romanian (Română)</option>
<option value="ru">Russian (Русский)</option>
<option value="sr">Serbian (српски језик)</option>
<option value="sr-SR">Serbian (srpski jezik)</option>
<option value="sk">Slovak (Slovencina)</option>
<option value="sl">Slovenian (Slovenski Jezik)</option>
<option value="es">Spanish (Español)</option>
<option value="sv">Swedish (Svenska)</option>
<option value="ta">Tamil (தமிழ்)</option>
<option value="th">Thai (ภาษาไทย)</option>
<option value="tj">Tajikistan</option>
<option value="tr">Turkish (Türkçe)</option>
<option value="uk">Ukranian (Українська)</option>
<option value="vi">Vietnamese (Tiếng Việt)</option>
<option value="cy-GB">Welsh/UK (Cymraeg)</option>
</select></p>
</body></html>
Referencias:
http://jqueryui.com/demos/datepicker/#localization
http://jquery-ui.googlecode.com/svn/trunk/ui/i18n/