Repair prestashop cart module (javascript code)

Hi,

i have a prestashop website, it is unitif.com, i have a cache module installed, the problem is when i activate the cache module i get a problem with the cart of the shop. The problem is, when i add a product to cart and then go to another page of the shop, the cart then looks empty but when i click on the cart the products are still inside the cart, it is just the popup preview of the cart that looks empty.

Here is the adress of my website to check the problem :
unitif.com

Tell me before you ckeck so i can activate the cache module so you can see the problem

Thanks.