function idioma() {
if (navigator.userAgent.indexOf("Opera")!=-1) (language=navigator.language)
    else { if (navigator.appName == "Netscape") (language=navigator.language) 
           else language=navigator.browserLanguage };
if(language){language=language.substring(0,2);}
else {language="zz";}
switch (language) {
   case "en" : window.location="index_en.html"; break;
   case "es" : window.location="index_es.html"; break;
   case "zz" : window.location="index_en.html"; break;
   default : window.location="index_en.html"; } }