Add to cart Button not working anymore

[EIF]

Since a few days my add to cart button isn't working anymore. When clicking on 'add to cart' there should be a pop-up saying the product is added to the cart. Now nothing happens... See for your self at: http://www.waterpijp-bong.nl

I did not make any file or setting changes. So it must be something at my hosting server.

I backed up my online website and restored it locally. And guess what: the button is working now, with same settings like fancybox, jquery, etc. The only difference is the PHP version. Locally I have 5.4.19 and my hosting provider 5.3.28. The strange thing is, that the version of my provider is 5.3 for a lot of months now. So how is it possible it doesnn't work now. It still seems to be a hosting issue. Can someone tell what PHP element this 'add to cart' button is needing? I need this get solved quickly.

[EIF]

Solved... I am using Rupostel One page.
Seems to be a Javascript Ajax issue... but it can be solved easy. Check here: http://www.rupostel.com/joomla/hacks/virtuemart-does-not-work-with-ajax-popup-when-adding-a-product
The only strange thing is issue occured suddenly...

[GJC Web Design]

If the response to the ajax add to cart call is "malformed"  i.e. perhaps an error reporting comes back with it (could tie in with php not being high enough version -- then the script fails

Rupostal's fix changes this behaviour which is why perhaps it works again - you can check the response  in the console tab of Firebug -

[EIF]

What also is strange that local the add-to-cart button just worked... only not online somehow.
But ok, it is fixed now and that's what counts ;-)

[GJC Web Design]

but you say that the php version is higher on your local.. a chance then that the error/notice etc wasn't triggered therefore didn't break the json response to the add to cart