Detect text in an external site

[apoc137]

Okay, first off I apologize but I am new to HTML and still learning, so sorry if this is an obvious question but I've been googling/researching/asking people for several days and I have come up with nothing worthwhile.

On my website, I have it set up to where when you load a certain page it opens a small pop-up that asks for a simple user input (btw this is the idea of the page...) however the pop-up that loads is an external page. After the user correctly enters the correct input on the pop-up (remember its external page) it takes the user to a 'confirmation page' that simply lets you know that you put the right input message in. Is there a way that in MY page I can insert a code that would detect the confirmation text inside the pop-up window?

Sorry if this doesn't make sense or isn't even possible, but I figured I may as well ask before I lose hope entirely.

[Medyman]

Do you have any control over the "external page"? You could do it, but you would need to alter the code that validates the input.

[apoc137]

No i have no control over the external page, hence why I have been having trouble with this.