function Delete($mysqli,$table_name, $where_clause=''){   


  $whereSQL = '';


  if(!empty($where_clause)) {


    // check to see if the 'where' keyword exists


    if(substr(strtoupper(trim($where_clause)), 0, 5) != 'WHERE') {


      // not found, add keyword


      $whereSQL = " WHERE ".$where_clause;


    } else {


      $whereSQL = " ".trim($where_clause);


    }


  }


  $sql = "DELETE FROM `".$table_name."` ".$whereSQL;


  return mysqli_query($mysqli,$sql);


}