如何在检测浏览器语言时停止javascript的无限循环

Question

My objective is to detect the user's language and redirect them to either a French page or English, with English being the default. This works if I put the code on the French page only and try to open the French page, this auto detects and loads the English. If I have the code on both then it just gets stuck in an infinite loop. Any help would be greatly appreciated. Here is the code.

<script language="javascript"> 

var langcodes=new Array("en", "fr", "default") ;

var langredirects=new Array("http://defaulten.asp", 
"http://default-fr.asp", 
"http://default.asp"); 

var languageinfo=navigator.language? navigator.language : navigator.userLanguage ;
var gotodefault=1 ;

function redirectpage(dest){ 
if (window.location.replace) 
window.location.replace(dest) 
else 
window.location=dest 
} 

for (i=0;i<langcodes.length-1;i++){ 
if (languageinfo.substr(0,2)==langcodes[i]){ 
redirectpage(langredirects[i]) 
gotodefault=0 
break 
} 
} 

if (gotodefault) 
redirectpage(langredirects[langcodes.length-1]) 

</script>

Answer 1

You need to make sure you don't re-direct if you are already on the correct page eg

if (languageinfo.substr(0,2)==langcodes[i]) {
    gotodefault = 0;
    var redirPage = langredirects[i];
    if (redirPage != document.URL)
        redirectpage(redirPage);
    break 
}

Also, if en is the default I wouldn't have a specific page for that ie defaulten.asp . I would only provide language specific pages ie default-fr.asp / default-us.asp , if you followed this approach your code would be even simpler eg

var languageinfo = navigator.language ? navigator.language : navigator.userLanguage;
languageinfo = languageinfo == "en" ? "" : languageinfo;
var langUrl = sprintf("http://default%s.asp", languageinfo);
if (document.URL != langUrl)
    redirectpage(langUrl);