# Checkbox - zTree methods

###### [ File Path: excheck/checkbox_fun.html ]

- ## 1, 'beforeCheck / onCheck' callback function

  - Use 'beforeCheck / onCheck' callback function can control whether to allow changes to the node check state. This simple demo shows how to monitor the check event.

  - By the way also demonstrates how to use the 'checkNode / checkAllNodes' method triggers 'beforeCheck / onCheck' callback, Try:
    setting.check.autoCheckTrigger: false
    Whether trigger the callback when execution checkNode() method.
    Node --[ check ] [ uncheck ] [ toggle ]
    Node (relationships) --[ check ] [ uncheck ] [ toggle ]
    All Nodes --[ check ] [ uncheck ]

  - How to use 'zTreeObj.checkNode / checkAllNodes' method, please see the API documentation.
    beforeCheck / onCheck log:

- ## 2, Explanation of setting

  - Same as 'Checkbox Operation'

- ## 3, Explanation of treeNode

  - Same as 'Checkbox Operation'