diff --git a/htdocs/main.inc.php b/htdocs/main.inc.php
index c8553f29291..9250384880b 100644
--- a/htdocs/main.inc.php
+++ b/htdocs/main.inc.php
@@ -959,11 +959,11 @@ function top_htmlhead($head, $title='', $disablejs=0, $disablehead=0, $arrayofjs
 
     if (empty($conf->css)) $conf->css = '/theme/eldy/style.css.php';	// If not defined, eldy by default
 
-    print '<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">';
+    //print '<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">';
     //print '<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/1999/REC-html401-19991224/strict.dtd">';
     //print '<!DOCTYPE HTML PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">';
     //print '<!DOCTYPE HTML PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">';
-    //print '<!DOCTYPE HTML>';
+    print '<!DOCTYPE html>';
     print "\n";
     if (! empty($conf->global->MAIN_USE_CACHE_MANIFEST)) print '<html lang="'.substr($langs->defaultlang,0,2).'" manifest="'.DOL_URL_ROOT.'/cache.manifest">'."\n";
     else print '<html lang="'.substr($langs->defaultlang,0,2).'">'."\n";
