Screw a window to the site with an inventory function like in browser-based online games?

Question

Java

The people, orient on the following question.
There is a site on WordPress. It is necessary in the personal accounts of visitors, to fasten the button by pressing which, in a new tab of the browser, a window is displayed with inventory capabilities as in games. In this window, various artifacts belonging to a particular visitor will be stored, things can be removed or added, read the characteristics of the object, i.e. browser-based online rpg inventory.
The question itself is... in Java, what technology stack is used for such an implementation, are there any lessons or examples explaining how to do this?