Get page keywords?

I'm looking to do something like AdWords or YPN, where it scans the current page for keywords and then provides relevant ads.

How could I get the text of a page while it's being displayed?

 

you can easily use PHP to get the text.

<?php
$url = 'http://www.blabla.com';
$file = fopen($url, 'r');
while(!feof($file))
{
$lines = fgets($file, 1024);
echo $lines;
}
fclose($file);
?>

 

Can I do that from a page that I'm trying to read? For example, if I put that code up on the top of the page and try to read that same page, will it read the entire page or only up to where the script is? Or will it loop, as each time it opens the page it'll re-run the same code?

 

That script read entire page
You can read ww.xyx.com/page.html and result to diaplay on ww.abc.com