All the app views and dialogs are inside an HTML DIV container with the
.app-dialog classes, respectively. On the other hand, the referred DIV container has an ID attribute value equals than the contained app view or dialog name.
Then, suposing that your app has a view with the name "mainView", you can refer to the view's DIV container element with the ID:
mainView, for example:
The case of the app frames is different than the app views and the app dialogs. As may you already know, the controls of the app frames are placed inside one or more Frame controls, then you can use the Frame control name as the selector of the app frame container.
Then, suposing you have an app view with the name "mainView", and, inside that view, you have a Frame control with the name "myFrame", showing an app frame inside, you can refer to the Frame control / app frame container like below:
Then you can refer, for example, to a "button1" Push button control, placed in an app view with the name "mainView", like below:
The app controls placed in app frames cannot be reached by identifiers. This is because you can show the same app frame (and therefore the same controls) in different Frame controls, inside the same app view or app dialog, but the HTML identifiers must be uniques.
To reach app controls placed inside app frames, and therefore inside Frames controls, you can take the controls names and use classes instead of identifiers. Remember to prefix the control name / class with the name of the Frame control's that show the app frame, that contain the control.