jquery jstree load sub_nodes on demand

I have a very large jstree and I am able to load it with json data but it takes a long time, I was wondering if there is a way to load the sub_nodes of each node upon click, and only load the parent nodes when the page loads开发者_如何转开发, anyone done this ? and can help I will appreciate.

I finally solved this problem, it is basically all related to the id that the jquery passes through ajax if it is 0 then it is first layer and if it other values it should all be handled in the server side code and considering the state value for the json the parent node and child node should be considered differently