Checked a checkbox on page refresh

I'm trying to keep a checkbox checked, but after I refresh the page, database is update with satus '1' but on front-end checkboxes is unchecked, hope somebody can help. Here is my code

<td>
   <span>
     <input type='checkbox' name='Id' value='".$checkSubRow['Checklist_Id']."' class='check' id='Completed-".$checkSubRow['Checklist_Id']."' onClick='Completed(".$checkSubRow['Checklist_Id'].")' 
            />
         echo (isset($_POST['checkbox']))? "checked='checked'": "";
 </span>
</td>