How can i run a callback function after Backbone.history.loadUrl?

Question

I tried the below code that does not work. Also i searched via google but find nothing. Backbone's official documentation does not have an entry about loadUrl.

app_router.on('route:page', function(id, name) {
    ...
});

app_router.on('route:file', function(id, name) {
      // first open the page
      Backbone.history.loadUrl("page", function() {
        // and open the file manager after page is loaded
      });
});

Answer 1

You cannot pass callback in loadUrl.

From annotated source

Attempt to load the current URL fragment. 
If a route succeeds with a match, returns true. 
If no defined routes matches the fragment, returns false.

And function definition

loadUrl: function(fragment)

Instead use

 router.on("route", function() {
   ...
 });

To answer your edited question, you can do something like

 app_router.on('route:file', function(id, name) {
    // first open the page
    if(Backbone.history.loadUrl("page")){
       // and open the file manager after page is loaded
    });
 });