Remove a parent node's child nodes
1. After remove child nodes, the parent node will become a leaf node. Such as the need to maintain the parent node is still a parent node, set 'setting.data.keep.parent' attribute.
2. Do not use this method to empty the root. If you need to empty the root, you can initialization zTree, and set the initial nodes is null.
3. This method does not trigger any callback function.
Please use zTree object to executing the method.
The parent node which need to clear its child nodes.
Please ensure that this data object is an internal node data object in zTree.
Return the parent node's child nodes which have been removed. If has no child nodes, return null.
var treeObj = $.fn.zTree.getZTreeObj("tree");
var nodes = treeObj.getSelectedNodes();
if (nodes && nodes.length>0) {
treeObj.removeChildNodes(nodes[0]);
}