iPhone browsers crashes using our webshop

Hi there fellow humans,

We're about to go live with our website and we're experiencing a big problem that we're hopeing someone experienced from the apple community can help us with.

Our temponary url: http://ny.healthy.se

Once you add a product and go to the checkout process ( http://ny.healthy.se/kassa/ ) the entire iPhone safari (/chrome) browser crashes. There's no problems using a desktop or a android / windows mobile device but we're experiencing this problem using only iPhone, we've tried both iPhone 4, iPhone 5 and iPhone 5S.

Could some experienced developer maybe take a look at it and help us with this issue? We're in a panic mode right now and we highly appreciate any help we can get!