Get the collection of nodes which be checked or unchecked. It is valid when [setting.check.enable = true]
Please use zTree object to executing the method.
checked = true means: get the collection of nodes which be checked
checked = false means: get the collection of nodes which be unchecked
If this parameter is omitted, it is same as 'checked = true'
Don't get the nodes which 'nochecked' attribute is true.
return the collection of nodes which be checked or unchecked. (Array)
var treeObj = $.fn.zTree.getZTreeObj("tree");
var nodes = treeObj.getCheckedNodes(true);