Best practice javascript and multilanguage

Question

what is the best practice for multilanguage website using DOM Manipulating with javascript? I build some dynamic parts of the website using javascript. My first thought was

Answer 1

function Language(lang)
{
    var __construct = function() {
        if (eval('typeof ' + lang) == 'undefined')
        {
            lang = "en";
        }
        return;
    }()

    this.getStr = function(str, defaultStr) {
        var retStr = eval('eval(lang).' + str);
        if (typeof retStr != 'undefined')
        {
            return retStr;
        } else {
            if (typeof defaultStr != 'undefined')
            {
                return defaultStr;
            } else {
                return eval('en.' + str);
            }
        }
    }
}

After adding this to your page, you can work with it like this:

var en = {
    SelPlace:"Select this place?",
    Save:"Saved."
};

var tr = {
    SelPlace:"Burayı seçmek istiyor musunuz?"
};

var translator = new Language("en");
alert(translator.getStr("SelPlace")); // result: Select this place?
alert(translator.getStr("Save")); // result: Saved.
alert(translator.getStr("DFKASFASDFJK", "Default string for non-existent string")); // result: Default string for non-existent string

var translator = new Language("tr");
alert(translator.getStr("SelPlace")); // result: Burayı seçmek istiyor musunuz?
alert(translator.getStr("Save")); // result: Saved. (because it doesn't exist in this language, borrowed from english as default)
alert(translator.getStr("DFKASFASDFJK", "Default string for non-existent string")); // result: Default string for non-existent string

If you call the class with a language that you haven't defined, English(en) will be selected.