I want to build a site like art.com, I can make a shopping cart by using any popular platform like magento, opencart or cs-cart, but the site which i mentioned has couple of unique feature, you can see them here


Once you go there, please click on "mats tab" and see how they have "how many mats would you like" and have 0,1,2,3 on it. I want to do this, user should also be able to change width of the mat down to 1" or increase as they prefer like shown here.

Also please check the "mat details" link, and then click on "change", here user can change the width of border.

How can I achieve all this, is there any Jquery plugin for it?

Can I do this thing with Jquery and AJAX?

When user has done all the changes how can I submit changed look and feel of the art into database, so that user can add it to cart to order further?

Please guide me from where should I start or learn and what are the best available platforms?

The code you mentioned is built with Flash. It is quite possible to build something like this in Javascript though. You'll need to read up on Javascript/AJAX at least.