I was working on/debugging an internal site of mine today and I started to receive some odd behavior when I was using a form that I hadn’t made changes to (which utilizes jQuery and FancyBox). I use FancyBox to show a dialog for a simple data entry form. This worked in every scenario except when I was running it through the debugger in Visual Studio 2013. If I started the site with "Ctrl-F5" it would work fine. It also worked fine from my Azure hosting.
The interesting thing was that when I would pause the site it would be stuck in a file called "browserlink" in code that was not mine. My first instinct was to disable all add-ons and try again (I use Web Essentials and it injections code into the page). I started Visual Studio in with the "/SafeMode" flag to no avail, it would still hang showing the form.
After researching the browserlink (which is new in VS2013) I learned I could also disable it. So I did this to test and the end result… the site started working fine again. I should also note the site is a WebForms site.
Add this line to the "appSettings" section of the "web.config".
<add key="vs:EnableBrowserLink" value="false" />
The other way to disable this is to uncheck the "Enable Browser Link" in Visual Studio. You can find this on the toolbar to the right of the play button. The icon looks like a refresh button.