diff --git a/src/display/api.js b/src/display/api.js
index b4603ca95..9f50deecc 100644
--- a/src/display/api.js
+++ b/src/display/api.js
@@ -1202,12 +1202,12 @@ var PDFWorker = (function PDFWorkerClosure() {
   let nextFakeWorkerId = 0;
 
   function getWorkerSrc() {
-    if (typeof workerSrc !== 'undefined') {
-      return workerSrc;
-    }
     if (getDefaultSetting('workerSrc')) {
       return getDefaultSetting('workerSrc');
     }
+    if (typeof workerSrc !== 'undefined') {
+      return workerSrc;
+    }
     if (typeof PDFJSDev !== 'undefined' &&
         PDFJSDev.test('PRODUCTION && !(MOZCENTRAL || FIREFOX)') &&
         pdfjsFilePath) {