Sorry, I couldn't think of a good title.
I would like to have the default pushstate behaviour, but have custom behaviour during certain situations. So I want all links to be normal /login, /register, etc. If the user is on the homepage, I want those links to go to their respective pages through backbone.
However, if the user is one a special page like /product/123, then we are going to show them a modal, and although the href says "/login" I want to simply call the route function to show the login page, append #login to the url (ie "/product/123#login") and add a push state with the hash-tag'd url.
The reasoning behind this, is that someone could be on /product/123, click /login, suddenly decide they want to share the product and have the product url available, then out of habit hit back, to go back to viewing the product [ie. close the login modal], and have it work as expected.
Is the above possible? From what i've been reading, backbone's history module is a set it and forget it kind of thing, and I was unable to see a way through the Backbone documentation.
It's probably not a good idea to have your modal in a route. For most use, a modal window is something that popups on the current page, it's not an actual view change, it's a view that is appended somewhere on top of whatever the user was doing (it's modal in the sense that the user can't continue what he was doing until he handles whatever popped up).
In that regards, the /login route should probably not be a modal but instead a full page view with a login form. Then on your other pages, I assume you have a Layout view that contains a sub-view somewhere that renders the "login modal" button, right? When click on this button, you can handle the modal rendering/appending to body (or however).
In this scenario, there is no need for a URL change, and so, Backbone router won't be involved. My point is that the use case you are describing would only make sense if it was interesting to share a URL (/product/123#login) that would re-open the login modal on the product/123 page (and not on another product)... and I think that's not a very useful feature! In my opinion (and this is very arguable, I am sure), the login modal isn't something that should have a specific route, because it's not an actual stable application path, if that makes sense.