Listing is empty?

Can anybody explain to me why this would happen?? This listing was made awhile ago on garagesale 6 but since I upgraded item number is …

It seems that you have entered your own code (HTML/javascript) which breaks the designs.

Can’t ever remember trying t change the HTML as I don’t have a clue how to do that so I don’t mess with it? I only ever change text etc in standard view. I have now copied and pasted another listing and it looks ok so hopefully that will do. Thanks