Is it possible to prevent iframe content from escaping into main page using JS?

It is often done by code like this:

if ( window.parent.frames.length>0 )  {}  // check how many frames, if none do nothing
else {
   window.location="[new destination]";  // else change the current location
}

But I want to prevent iframe content fro开发者_如何转开发m knowing that it is on the iframe. I am writing a php proxy and content will be from the same domain and I know that I have an option to remove instances of escaping code one by one using server side code but maybe is there an option to do it in JS.