Merge pull request #6145 from edx/will/fix-mktg-iframe-redirect

Fix issue with iframe redirect

lms/templates/courseware/mktg_course_about.html

@@ -22,7 +22,9 @@
 
       var email_opt_in = $("input[name='email_opt_in']").val(),
         current_href = $("a.register").attr("href");
-      $("a.register").attr("href", current_href + "&email_opt_in=" + email_opt_in)
+      if (current_href) {
+        $("a.register").attr("href", current_href + "&email_opt_in=" + email_opt_in)
+      }
 
       $("#class_enroll_form").submit();
       event.preventDefault();