how can I make a page opening only into the iframe and not if it's called directly?

Question

The content generate by list.php should be only opened into an iframe tag, on the index.php. But when it's called directly, it should not be possible to open it. How can I obtain this?

In fact I already adopete this method:

<iframe title="frame" class="iframe" src="http://www.example.com/list.php?type=a&amp;013acd2b6c1368f">[Your browser doesn%27;t support iframes]</iframe>

which works fine, thus if the file is called without the arguments ,it redirects to the index.

BUT if you call it directly in this way http://www.example.com/list.php?type=a&013acd2b6c1368f the content appears at full page. While I want that, being outside the tag , it redirects to Index.php

Is there any way please?

Answer 1

I'm sorry to any one.

After have written this message, I finally found the answer here and with small adaption it worked out perfectly. I didn't find this post before.

Answer to my question