From db38b71dd9994e7d27e957cc05e59ed08cd0d758 Mon Sep 17 00:00:00 2001
From: Chris Adams <chris@improbable.org>
Date: Thu, 27 Jun 2013 16:02:17 -0400
Subject: [PATCH] makeAjaxRequest: throw error for missing callback

---
 src/openseadragon.js | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/openseadragon.js b/src/openseadragon.js
index 2a6e2689..12c11ade 100644
--- a/src/openseadragon.js
+++ b/src/openseadragon.js
@@ -1313,6 +1313,10 @@ window.OpenSeadragon = window.OpenSeadragon || function( options ){
         makeAjaxRequest: function( url, onSuccess, onError ) {
             var request = $.createAjaxRequest();
 
+            if (!$.isFunction(onSuccess)) {
+                throw new Error( "makeAjaxRequest requires a success callback" );
+            }
+
             request.onreadystatechange = function() {
                 // 4 = DONE (https://developer.mozilla.org/en-US/docs/Web/API/XMLHttpRequest#Properties)
                 if ( request.readyState == 4 ) {