gistfile1.txt

// Filter
public class CorsFilter : ActionFilterAttribute
{
    public override void OnActionExecuted(ActionExecutedContext filterContext)
    {
        base.OnActionExecuted(filterContext);

        var response = filterContext.RequestContext.HttpContext.Response;
        // Add header to response
        response.AddHeader("Access-Control-Allow-Origin", "*");
        response.AddHeader("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept");
        response.AddHeader("Access-Control-Allow-Methods", "GET, PUT, POST, DELETE, OPTIONS");
    }
}

// New controller
public class Test3Controller : Controller
{
    [CorsFilter]
    [HttpPost]
    public ActionResult Xlsx(string data, string name)
    {
        /* ... implementation here ... */
    }
}