Please share your code for using the JavaScript core library to access a shared data extension.

I can confirm that the following works which uses SSJS Platform functions:

<script runat="server">
     var dataRows = Platform.Function.LookupRows('ENT.My Favorite Shared DE','Key','1');
     Platform.Response.Write(dataRows.length);
     if(dataRows && dataRows.length > 0) {
          for(var i=0; i<dataRows.length; i++) {
               Platform.Response.Write(dataRows[i]["Key"]);
          }
     }
</script>

http://help.exacttarget.com/pt/documentation/exacttarget/conteudo/javascript_do_servidor/guia_de_sintaxe/platform_server_side_javascript_functions/interacting_with_data_extensions_using_the_function_object/

Please share your code for using the JavaScript core library to access a shared data extension.

I can confirm that the following works which uses SSJS Platform functions:

<script runat="server">
     var dataRows = Platform.Function.LookupRows('ENT.My Favorite Shared DE','Key','1');
     Platform.Response.Write(dataRows.length);
     if(dataRows && dataRows.length > 0) {
          for(var i=0; i<dataRows.length; i++) {
               Platform.Response.Write(dataRows[i]["Key"]);
          }
     }
</script>

Reference: Interacting with Data Extensions Using the Function Object