From eabda590c88185a75cb7ec621a0d210d2cf1418a Mon Sep 17 00:00:00 2001
From: Jay Dansand <dansandj@lawrence.edu>
Date: Wed, 14 Feb 2018 08:27:29 -0600
Subject: [PATCH] Prevent setting alt=String("undefined") when the original IMG
 has no alt.

---
 src/js/image.js | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/js/image.js b/src/js/image.js
index f5687c85..fc389c6e 100644
--- a/src/js/image.js
+++ b/src/js/image.js
@@ -190,7 +190,11 @@ $.magnificPopup.registerModule('image', {
 				var img = document.createElement('img');
 				img.className = 'mfp-img';
 				if(item.el && item.el.find('img').length) {
-					img.alt = item.el.find('img').attr('alt');
+					// Sometimes the img does not have an alt attribute. jQuery 1.6+ will
+					// then return /undefined/, setting img.alt=String("undefined").
+					if(item.el.find('img').attr('alt')) {
+						img.alt = item.el.find('img').attr('alt');
+					}
 				}
 				item.img = $(img).on('load.mfploader', onLoadComplete).on('error.mfploader', onLoadError);
 				img.src = item.src;