diff --git a/htdocs/core/class/html.form.class.php b/htdocs/core/class/html.form.class.php
index 549959bd561..552eed53a94 100644
--- a/htdocs/core/class/html.form.class.php
+++ b/htdocs/core/class/html.form.class.php
@@ -4164,7 +4164,7 @@ class Form
             else
 			{
                 // Day
-                $retstring.='<select'.($disabled?' disabled':'').' class="flat" name="'.$prefix.'day">';
+                $retstring.='<select'.($disabled?' disabled':'').' class="flat" id="'.$prefix.'day" name="'.$prefix.'day">';
 
                 if ($emptydate || $set_time == -1)
                 {
@@ -4178,7 +4178,7 @@ class Form
 
                 $retstring.="</select>";
 
-                $retstring.='<select'.($disabled?' disabled':'').' class="flat" name="'.$prefix.'month">';
+                $retstring.='<select'.($disabled?' disabled':'').' class="flat" id="'.$prefix.'month" name="'.$prefix.'month">';
                 if ($emptydate || $set_time == -1)
                 {
                     $retstring.='<option value="0" selected>&nbsp;</option>';
@@ -4196,11 +4196,11 @@ class Form
                 // Year
                 if ($emptydate || $set_time == -1)
                 {
-                    $retstring.='<input'.($disabled?' disabled':'').' placeholder="'.dol_escape_htmltag($langs->trans("Year")).'" class="flat" type="text" size="3" maxlength="4" name="'.$prefix.'year" value="'.$syear.'">';
+                    $retstring.='<input'.($disabled?' disabled':'').' placeholder="'.dol_escape_htmltag($langs->trans("Year")).'" class="flat" type="text" size="3" maxlength="4" id="'.$prefix.'year" name="'.$prefix.'year" value="'.$syear.'">';
                 }
                 else
                 {
-                    $retstring.='<select'.($disabled?' disabled':'').' class="flat" name="'.$prefix.'year">';
+                    $retstring.='<select'.($disabled?' disabled':'').' class="flat" id="'.$prefix.'year" name="'.$prefix.'year">';
 
                     for ($year = $syear - 5; $year < $syear + 10 ; $year++)
                     {