window close

Hi all,
On click of hyperlink, i am cerating one popup which is under one div
having class but no id.
On click of "close window" hyperlink in the popup i want to hide this
popup.
But not able to hide this.
I tried this, but not working
$(this).parent('.popup_window_wrapper').css({'display':'none'});
popup_window_wrapper: Is the class of popup div.
Please help me.