diff --git a/addons/web/static/src/js/search.js b/addons/web/static/src/js/search.js
index e34776896d8..49fb60b99ac 100644
--- a/addons/web/static/src/js/search.js
+++ b/addons/web/static/src/js/search.js
@@ -967,8 +967,7 @@ openerp.web.search.DateField = openerp.web.search.Field.extend(/** @lends opener
         this.datewidget.prependTo(this.$element);
         this.datewidget.$element.find("input")
             .attr("size", 15)
-            .attr("autofocus", this.attrs.default_focus === '1' ?
-                                   'autofocus' : undefined)
+            .attr("autofocus", this.attrs.default_focus === '1' ? 'autofocus' : null)
             .removeAttr('style');
         this.datewidget.set_value(this.defaults[this.attrs.name] || false);
     },