I have implemented draggable and droppable jquery functions. They work.
However, they stop working if I reload a part of the website.
For example, I reload a div containing draggable items via AJAX (to get updated items) and suddenly I cannot drag and drop these new items. Though I do not reload the part of the web page with javascript code so it should still work.
When you reload the div containing the draggable items, you are removing the draggable functionality from them (they are new DOM elements rather than the old ones that had draggable attached to them).
You need to re-attach the draggable functionality each time you load those divs. Here’s an example of how to use jQuery.live() to achieve what you need:
JQuery Live and Draggable