A little help with our store's website, please?

[vespiz]

Whoa! Didn't expect this much help! Much appreciated!

I'll have a look at the code at some point, but as I said before, I didn't do the original work and CSS and stuff like that just escapes me.
Basic HTML is easy.. but whadaheck is jquery? Ajax (dishwashing soap?)??

 

[Steven Otto]

jQuery is a javascript library. Using javascript can be pretty tedious so that's why jQuery was created. It allows you to use sophisticated javascript with very few lines of codes.

Javascript is used to add behavior to a site, like form validation or a slidehow.

AJAX stands for Asynchronous Javascript And XML. With AJAX you can run a script on the background which doesn't interfere with the current display / page.
An example of AJAX would be when a new comment appears while watching a YouTube video. You see a new comment without the need to refresh the page nor does it interrupt your video playback.

To put it in some perspective:
HTML - Content
CSS - Design
Javascript (jQuery) - Behavior

I hope it made some sense