How do you add a paypal button to a thread?

There is either this to add:

<form action="https://www.paypal.com/cgi-bin/webscr" method="post">
<input type="hidden" name="cmd" value="_s-xclick">
<input type="hidden" name="hosted_button_id" value="UERL8KTYU7G5J">
<input type="image" src="https://www.paypal.com/en_US/GB/i/btn/btn_donateCC_LG.gif" border="0" name="submit" alt="PayPal - The safer, easier way to pay online.">
<img alt="" border="0" src="https://www.paypal.com/en_GB/i/scr/pixel.gif" width="1" height="1">
</form>

or this:

https://www.paypal.com/cgi-bin/webscr?cmd=_s-xclick&hosted_button_id=UERL8KTYU7G5J

Neither add a button?