From 565e7cd097cf0aabb8bae8ad7c84d470b2ff906e Mon Sep 17 00:00:00 2001
From: Hasse Feldthaus <hafe@kb.dk>
Date: Wed, 29 Jul 2015 17:16:19 +0200
Subject: [PATCH] Added XDomainRequest as fallback method for ajax, if
 XMLHttpRequest fails.

---
 src/openseadragon.js | 36 ++++++++++++++++++++++++++++++++++--
 1 file changed, 34 insertions(+), 2 deletions(-)

diff --git a/src/openseadragon.js b/src/openseadragon.js
index 64349972..0d2c894c 100644
--- a/src/openseadragon.js
+++ b/src/openseadragon.js
@@ -2045,8 +2045,40 @@ window.OpenSeadragon = window.OpenSeadragon || function( options ){
 
                 request.onreadystatechange = function(){};
 
-                if ( $.isFunction( onError ) ) {
-                    onError( request, e );
+                if (window.XDomainRequest) { // IE9 or IE8 might as well try to use XDomainRequest
+                    var xdr = new XDomainRequest();
+                    if (xdr) {
+                        xdr.onload = function (e) {
+                            if ( $.isFunction( onSuccess ) ) {
+                                onSuccess({ // Faking an xhr object
+                                    responseText: xdr.responseText,
+                                    status: 200, // XDomainRequest doesn't support status codes, so we just fake one! :/
+                                    statusText: 'OK'
+                                });
+                            }
+                        }
+                        xdr.onerror = function (e) {
+                            if ( $.isFunction ( onError ) ) {
+                                onError({ // Faking an xhr object
+                                    responseText: xdr.responseText,
+                                    status: 444, // 444 No Response
+                                    statusText: 'An error happened. Due to an XDomainRequest deficiency we can not extract any information about this error. Upgrade your browser.'
+                                });
+                            }
+                        }
+                        try {
+                            xdr.open('GET', url);
+                            xdr.send();
+                        } catch (e) {
+                            if ( $.isFunction( onError ) ) {
+                                onError( request, e );
+                            }
+                        }
+                    }
+                } else {
+                    if ( $.isFunction( onError ) ) {
+                        onError( request, e );
+                    }
                 }
             }
         },