Triggers determine how actions are activated in media clips, pages, and form fields. For example, you can specify a movie or sound clip to play when a page is opened or closed. The available options depend on the specified page element.
You can use the following triggers for media clips and form fields (not links or bookmarks):
When the mouse button is released after a click. This is the most common button trigger, because it gives the user one last chance to drag the pointer off the button and not activate the action.
When the page containing the media clip is visible, regardless of whether it is the current page. It’s possible for a page to be visible without being the current page, such as when a continuous page layout displays pages side-by-side.
When the page containing the media clip is moved out of view.
When the page containing the media clip becomes the current page.
When a user leaves the page that contains the media clip.
When the mouse button is clicked (without being released). In most cases, Mouse Up is the preferred trigger.
When the pointer enters the field or play area.
When the pointer exits the field or play area.
When the link area receives focus, either through a mouse action or tabbing.
When the focus moves to a different link area.