Not quite the same way, but you could use an IMG tag that runs the cron:
Code:
<img src="cron.php" width="1" height="1" border="0">
The cron.php file should contain something like the following:
Code:
header("Location: http://www.domain.com/images/dot.gif");
do_my_cron();
Where the do_my_cron function contains the PHP code you'd like to run.
If you use this method, then anytime some hits a page containing your IMG tag, your cron job is run.