IE9- and Backbone.history's pushState

app.js

//in your application, rather than using window.location to get the current url
App.getLocation = function(){
    return window.location.protocol + '//' + window.location.host 
              + '/' + Backbone.history.options.root + Backbone.history.getFragment()
}

bootstrap.js

//when your application starts up
Backbone.history.start({
  pushState: Modernizr.history,
  silent: true
});

if (!Modernizr.history) {
  rootLength = Backbone.history.options.root.length;
  fragment = window.location.pathname.substr(rootLength);
  search = window.location.search;
  return Backbone.history.navigate(fragment + search, {
    trigger: true
  });

} else {
  return Backbone.history.loadUrl(Backbone.history.getFragment());
}