My problem

I'm trying to put a map on a webpage, the data being fetch with Ajax. It works fine with all browsers, but not IE9.

I get an error:

SCRIPT5007: Unable to get value of the property 'ajax': object is null or undefined

and the map does not load.

The code

       var mapModel = new Map(); 



       mapModel.get(leads).fetch({success: function(){ //error on this line

              var mapView = new MapView({ model: mapModel });

              $('body').append(mapView.el);

              mapView.render();

           }});

What I tried

This seems to be a very common issue, here is the most up-voted question on the subject. So I tried to put

 <meta http-equiv=X-UA-Compatible content=IE=8/>

but it didn't solve anything.

My question

What I should I do to fix this problem?