How to search for a string in the external source iframe?

I'm trying to find a way to search the contents of the external iframe.. How to do that?

I know that I can't traverse the external iframe using javascript.., but what about PHP? Can I implement a script in PHP tha开发者_JAVA百科t will scan the contents of the external iframe? How?

You could use cUrl (or maybe fread) to read the contents of the url that is in the src of your iframe, but there is no garantee that the contents will be the same. The page that is rendered inside the iframe might depend on session data, cookies, referee...