I've been racking my brain about this and I am hoping others may help. I have two host-name site collections http://site1 and http://site2. These are both within the same SharePoint Web Application and I have not built any SharePoint (or Provider) hosted apps.
I've added a JS script to one of the pages within http://site1 that needs to access information from http://site2 over AJAX (right now I am using jQuery). When trying to do this am getting a Cross Domain error from the browser.
Has anyone had any luck trying to add a simple ASPX page into the SharePoint 'Pages' library, adding a JS snippet which hits a document library from another site collection, that is under a different domain?