Best JavaScript i18n techniques / Ajax - dates, times, numbers, currency

<script>
    i18n_dict = {'how old':'Ich bin %s Jahre alt'};
    function test_i18n(){
        alert($.i18n._('how old','5');
    }
</script>
<a onclick="test_i18n()">clickme</a>

<script type="text/javascript" src="../../../dojo/dojo.js"
  djConfig="isDebug: true, parseOnLoad: true, locale:'de'"></script>

{name: 'Column 5', field: 'col5', formatter: dojo.number.format },

<script type="text/javascript" src="jquery.i18n.properties-min.js"></script>
<div class="i18n_label:foo">placeholder text</div>

i18n_label:foo=bar

$.i18n.properties({
    name: 'Messages',
    mode: 'map'
});

$('[class*="i18n_label:"]').each(function(index, elem) {
    $(elem.classList).each(function(index, classname) {
        if (!classname.match(/i18n_label:/))
            return;
        var newval = $.i18n.prop(classname);
        if (newval)
            $(elem).text(newval);
    });
});