diff --git a/html5_tools.module b/html5_tools.module
index 862f91a..0145f9f 100644
--- a/html5_tools.module
+++ b/html5_tools.module
@@ -333,12 +333,12 @@ function _numberfield_html5_tools_field_widget_forms(&$form, &$form_state, $fiel
   );
 
   // Add min attribute.
-  if (!empty($instance['settings']['min']) || $instance['settings']['min'] === '0') {
+  if (isset($instance['settings']['min']) && $instance['settings']['min'] !== '') {
     $element['#min'] = $instance['settings']['min'];
   }
 
   // Add max attribute.
-  if (!empty($instance['settings']['max'])) {
+  if (isset($instance['settings']['max']) && $instance['settings']['max'] !== '') {
     $element['#max'] = $instance['settings']['max'];
   }