Thank you all for explaining so patiently, I have somewhat of understanding with this issue ~ very appreciated all who commented. Jerry ----------------------------------------------------------------- Yahoo!©_¼¯¹q¤l«H½c 100MB §K¶O«H½c¡A¹q¤l«H½c·s¬ö¤¸±q³o¶}©l¡I http://mail.yahoo.com.tw/