Calling a function in a parent JSP or a parent JSP in a child JSP page calling a function in a child page

Project scenario:

One of the Window,window embedded in the a.jsp is a <iframe> another page b.jsp is introduced through <iframe>. A function Funa defined in a.jsp needs to be called in a function in b.jsp.

At this time, can be in b.jsp JS in the Parent.funa () to invoke the Funa method in a.jsp;

The parent page invokes the method in the child page in the IFRAME:

' window.frames[' Childpage "].SONFF ();

Calling a function in a parent JSP or a parent JSP in a child JSP page calling a function in a child page