如何限制jstree 只能有一個root

直接服用下面的設定值即可，everything you have to use is

"types" : {     
       "#" : {
            "max_children" : 1
        }
    },

資料來源：jstree drag and drop restrict node before and after root
https://stackoverflow.com/questions/13024417/jstree-drag-and-drop-restrict-node-before-and-after-root