如何将值从外部页面传递到框架内？

I have a files inside a page , this page named (mainframe.php) is a frameset contain two subframes files (file 1 : topframe.php , file 2 bottom frame.php) and i need to pass a value from an external page(file:extarnalpage.php) to inside the frmams(topframe and bottomframe). but I can not do that...and the pages is as the followin:I have a files inside a page , this page named