diff --git a/htdocs/core/class/html.formfile.class.php b/htdocs/core/class/html.formfile.class.php
index c982e3d4bb2..56d3b5e29fb 100644
--- a/htdocs/core/class/html.formfile.class.php
+++ b/htdocs/core/class/html.formfile.class.php
@@ -869,7 +869,7 @@ class FormFile
     			else $this->infofiles['extensions'][$ext]++;
 
     			// Preview
-    			if (! empty($conf->use_javascript_ajax) && ! empty($conf->browser->layout != 'phone'))
+    			if (! empty($conf->use_javascript_ajax) && ($conf->browser->layout != 'phone'))
     			{
                     $tmparray = getAdvancedPreviewUrl($modulepart, $relativepath, 1);
                     if ($tmparray && $tmparray['url']) $tmpout.= '<li><a href="'.$tmparray['url'].'"'.($tmparray['css']?' class="'.$tmparray['css'].'"':'').($tmparray['mime']?' mime="'.$tmparray['mime'].'"':'').($tmparray['target']?' target="'.$tmparray['target'].'"':'').'>'.img_picto('','detail').' '.$langs->trans("Preview").' '.$ext.'</a></li>';
diff --git a/htdocs/main.inc.php b/htdocs/main.inc.php
index 8fe2125251c..5e015cd9f62 100644
--- a/htdocs/main.inc.php
+++ b/htdocs/main.inc.php
@@ -1899,7 +1899,7 @@ if (! function_exists("llxFooter"))
 
         if (! empty($delayedhtmlcontent)) print $delayedhtmlcontent;
 
-        // TODO Move this in lib_head.js
+        // TODO Move this in lib_head.js.php
 
         // Wrapper to show tooltips (html or onclick popup)
         if (! empty($conf->use_javascript_ajax) && empty($conf->dol_no_mouse_hover))
@@ -1922,7 +1922,7 @@ if (! function_exists("llxFooter"))
         }
         
         // Wrapper to manage document_preview
-        if (! empty($conf->use_javascript_ajax) && ! empty($conf->browser->layout != 'phone'))
+        if (! empty($conf->use_javascript_ajax) && ($conf->browser->layout != 'phone'))
         {
             print "\n<!-- JS CODE TO ENABLE document_preview -->\n";
             print '<script type="text/javascript">