设置用户隐藏的iFrame复选框

Can someone please let me know that if I have a web page that consists of a checkbox (parent) and on this same web page, I also have a iframe that is sourced from another page that displays a number of records, which also has a checkbox (children) against each record, if I tick the parent checkbox and assume the iframe is hidden from the user (have a feature to show/hide iframe), can I set all children checkboxs within this hidden iframe or does the iframe need to be rendered?Can someone please let me know that if I have a