Merge pull request #3759 from Snuffleupagus/issue-3755

Fix external links in Presentation Mode (issue 3755)

web/page_view.js

@@ -127,7 +127,9 @@ var PageView = function pageView(container, id, scale,
         }
         return false;
       };
-      link.className = 'internalLink';
+      if (dest) {
+        link.className = 'internalLink';
+      }
     }
 
     function bindNamedAction(link, action) {