[TYPO3-shop] How to hide ###PRODUCT_WWW### when field I empty

[Jogvan Olsen]

I using the 'www' field to link to manufactures homepage so the user can get 
some more info on the products.

I use a small image/icon as a link button.

My problem is that the link icon/image shows up (in FE) even when the 'www' 
is empty.

Does anybody know how I can hide the link icon when the 'www' field is 
empty, and show up when I type a web-address in to the 'www' field?


---- I have this in my html template ----
<!--###PRODUCT_WWW###-->  <a href="###PRODUCT_WWW###" target="_blank" > <img 
src="/fileadmin/images/menu/more_info.gif" border="0" alt=""> </a> 
<!--###PRODUCT_WWW###-->


I am using tt_products 2.4.3 and Typo 3 ver. 3.8.1


Thanks in advance
Jogvan Olsen