# Stopping Dynamic Actions using apex.da.cancelEvent
_Update: [Nick Buytaert](https://twitter.com/nbuytaert1) wrote a follow-up article on the [`apex.da.resume`](http://apexplained.wordpress.com/2014/01/18/the-apex-da-resume-function/) function. I suggest reading it along with this article in case you need to resume a Dynamic Action (which is especially useful for plugins)._
They're a few times when you may need to stop a Dynamic Action part way through the executing all its actions. Since individual actions don't have conditions associated with them there's no supported way to do this. Thankfully there's an undocumented JavaScript (JS) function called `apex.da.cancelEvent`. Here's an example of how to use it:
Suppose you have a page with two items, `P1_X` and `P1_Y`, and a button on P1. When the user clicks the button the Dynamic Action (DA) needs to set `P1_X = X` and `P1_Y = Y`. The DA setup will look like the following:
[](http://3.bp.blogspot.com/-e6yhj7M1vgE/Uso4eh2QGGI/AAAAAAAAEj8/qT56EVu5mfE/s1600/Edit-Dynamic-Action.png)
When you click the button `P1_X` and `P1_Y` are set to `X` and `Y` respectively.
Now suppose that after `P1_X` is set you wanted to stop all other actions in the DA (in this case setting `P1_Y`). There's no way to declaratively do this. Instead you must use the `apex.da.cancelEvent` function.
Add a new JavaScript `True Action` to the existing DA with sequence `15` (so its between the two other actions). In the code section use: `apex.da.cancelEvent.call(this);` Be sure to uncheck the `Fire On Page Load` option. The updated DA will look like image below (the new action is highlighted).
[](http://4.bp.blogspot.com/-Zjm1fMjGnFc/Uso_x_2VhJI/AAAAAAAAEkM/8JHhq8GPd_E/s1600/Edit-Dynamic-Action-1.png)
If you refresh P1 and click the button associated to this DA only `P1_X` will be set. The third action in this DA will not be executed.
The above example probably isn't the best use case for leveraging `apex.da.cancelEvent` however it does highlight its functionality. It is useful if you create your own custom confirm notice or some other process that determines if the rest of the actions in a DA can occur.
Note: You'll notice that I used the additional `call()` function when calling `apex.da.cancelEvent` in the action. Calling it defines the value of `this` in the function call as it is required in the `cancelEvent` function. For more information please read the JS [`call()` documentation](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function/call).