The Call JavaScript action lets you use the Behaviors panel to specify that a custom function or line of JavaScript code should be executed when an event occurs. (You can write the JavaScript yourself, or you can use code provided by various freely available JavaScript libraries on the web.)
For example, to create a Back button, you might type if (history.length > 0){history.back()}. If you have encapsulated your code in a function, type only the function name (for example, hogback()).
If it isnt, select another event from the pop-up menu. If the events you want are not listed, change the target browser in the Show Events For pop-up menu.