Issue #3173923: Apply some changes from #4, add tests

Closes #3173923

js/infinite-scroll.js

@@ -60,6 +60,14 @@
       // Add the new rows to existing view.
       .append($newRows);
 
+    // Set focus to the first link in the first row result.
+    if ($newRows.length > 0) {
+      var $newFocus = $($newRows[0]).find('a');
+      if ($newFocus.length > 0) {
+        $newFocus[0].focus();
+      }
+    }
+
     // Replace the pager link with the new link and ajaxPageState values.
     $existingPager.replaceWith($newPager);