how to pass value from popup window to php program

Hi all, I met one problem as below. To express clearly i use some psu-code instead: //this is php code if ($need_user_email_address) { //we popup a window to let user fill his/her email popup_window($give_me_your_email); //we get the user email from the popup window echo "your email is $give_me_your_email \n"; } I do not know whether it can be implemented or not, if it can be done, i really do not know how to produce the popup window and how to pass value from the popup window to the php main code. Thanks in advance! zhunbao __________________________________________________ Do You Yahoo!? Send FREE Valentine eCards with Yahoo! Greetings! http://greetings.yahoo.com