zTree获取（子）节点

var ids=[];
ids=getChildren(ids, treeNode);//TreeNode是选中节点，ids是子节点id数组，格式：123,223,4,55

1.获取直接子节点的id

//返回值包含选中节点的id，即ids[0]
function getChildren(ids, treeNode) {
   ids.push(treeNode.id);//选中节点id，即父节点id
   if (treeNode.isParent) {
       for (var obj in treeNode.children) {
            getChildren(ids, treeNode.children[obj]);
       }
   }
   return ids;
}

2.获取全部子节点id

//返回值是否包含选中节点id，根据情况而定
function getChildren(ids, treeNode) {
   ids.push(treeNode.id);//选中节点id，即父节点id
   if (treeNode.isParent) {
       for (var obj in treeNode.children) {
            ids.push(treeNode.children[obj].id);
       }
   }
   return ids;
}

 3.获取某节点的所有子节点

function getChildrenNodes(nodes, treeNode) {
   nodes.push(treeNode);
   if (treeNode.isParent) {
        for(var obj in treeNode.children) {
            getChildrenNodes(nodes, treeNode.children[obj]);
        }
   }
   return nodes;
}

 4.获取zTree的全部节点

var nodes = [];
var treeObj = $.fn.zTree.getZTreeObj("treeDemo");//zTree对象
var roots = treeObj.getNodes(); //所有一级节点
for (var i = 0; i < roots.length; i++) {
    nodes = getChildrenNodes(nodes, roots[i]);
}