Complicating the HTML5 routing and IE9 issue was the fact that AngularJS looks fundamentally broken regarding behavior around http settings.  Our server offers content negotiation, so an application url for /widgets requesting a content Accept header of text/html will result in the server sending HTML for the set of widgets it knows about.  If, however, the Accept type header is set to application/json, the server will respond with a json object with an array property containing widget data.

Our first problem is that a user browsing the site will want a full HTML page while Angular provides no facility (that I’ve found) for specifying an element in a full page to gather for the view.  It expects an HTML fragment consisting of a single root element.  To tackle this problem, we added an “X-Partial” header to let the server know to include only the partial content.

This worked fine and setting the $http settings is clearly documented…but also starts to have a code smell.  The $routeProvider doesn’t seem to have a way to specify http settings, so the only way to set headers is by setting http defaults.

As it turns out, while they are named defaults, they are not, in fact, defaults.  Deep in the code of AngularJS, you’ll see the following calls: