Old Proxomitron Forums

Proxomitron Program - discussions welcome => Questions and Answers => Topic started by: hpguru on June 17, 2002, 01:09:24 AM

Title: Cache-busting LUBID bug
Post by: hpguru on June 17, 2002, 01:09:24 AM
Anyone familiar with this? I find it here and there. It is an obvious web bug but what is "Cache-busting" about it?


<script language="JavaScript">
<!--
// Cache-busting LUBID bug.
var ran = Math.round(Math.random() * 899999) + 100000;
var lubid_string = "<img src="http://lubid.lycos.com/one.asp?site=members.tripod.com&ord=" + ran + "" height="1" width="1">";
document.write(lubid_string);
//-->
</script>



Facing each other,
a thousand miles apart.
Title: Cache-busting LUBID bug
Post by: Scott Lemmon on June 17, 2002, 04:58:23 AM
They probably mean the URL is rigged to change randomly so the browser calls the bug each time the page loads rather than caching it (like it would a normal image).

 
Title: Cache-busting LUBID bug
Post by: hpguru on June 17, 2002, 06:45:39 AM
Thanks Scott.

Facing each other,
a thousand miles apart.
Title: Cache-busting LUBID bug
Post by: pooms on June 17, 2002, 06:47:26 PM
I would guess that the image itself isn't what is important, but that
the browser does an HTTP GET. As Scott says, putting the random number
in the URL would avoid the browser serving a cached copy. The ASP
probably serves the same image no matter what random number is in the
URL. But by forcing an HTTP GET, the ASP gets access to the HTTP
headers, so it could use "Referer" to count page hits, or use cookies
to do other tracking.