Question: I have moment using the [momentjs-rails](https://github.com/derekprior/momentjs-rails) gem, and I have added the Spanish locale in `javascripts/moment/es.js`. I use the I18n gem and I'm unable to switch the `moment` language when I switch the app's global language. 

Adding , `moment.locale('es');` makes it show in Spanish, and adding; `moment.locale('en');` makes it show in English but it won't change with I18n.

I have tried in application.js.erb 

```
<% if I18n.locale == :es %>
     moment.locale('es');
<% end %>
<% if I18n.locale == :en %>
     moment.locale('en');
<% end %>

```

but `moment`'s language stays as the 'top' option, in this case 'es'.

So with;

```
<% if I18n.locale == :en %>
     moment.locale('en');
<% end %>
<% if I18n.locale == :es %>
     moment.locale('es');
<% end %>

```

the top option is 'en' so it displays in English.

How can I make moment.js language change when I change the language in I18n????

Answer: 
Put this code in application.html,switch the language and refresh page. Check whether it works for you instead of putting it to application.js.erb.

```
 <script type="text/javascript">
   <% if I18n.locale == :en %>
     moment.locale('en');
   <% end %> 
   <% if I18n.locale == :es %>
     moment.locale('es');
   <% end %> 
</script>

```

Thanks
To do this you will need to put down the actual i18n language of the web to js, can be done like this:

in main layout or application.js

```
var i18n_locale = "<%= I18n.locale %>"

```

and when you will initialize momentjs:

```
moment.locale('en');

```

I hope that it helps.