Google Script: Enterprise Application Essentials

Chapter 4. Adding Actions

In Chapter 3, you began creating an application to collect email addresses from visitors who would like you to contact them about whatever it is that you do. The only problem is that clicking your “Sign Up” button doesn’t do anything. In this chapter, we will add actions to that button to store the visitor’s email address, thank them if they entered an email address, and ask them to try again if they didn’t.

Handling a Handler

To make a button work it needs a handler. However, buttons are not the only widgets that can have a handler, and clicking on something is not the only handler type. For example, a text box may have a handler that responds to pressing the Enter key, or a list box sometimes needs to fill a second list for situations like choosing a city after the state has been selected. In that case, we might use an onChange handler. In more advanced UIs, mouse handlers, like “over” and “off,” can create rich user interaction by displaying information before a selection is made. It’s also important to note that a widget can have more than one handler. When you have a process that may take some time, like receiving data from a web service or uploading files from the hard drive, it’s a good idea to show a progress indicator to the user after the click something.

In this chapter, we will keep things simple and only work with the onClick handler to provide action for our simple form.

Some of the handlers in the UiApp:

• BlurHandler

• ChangeHandler

• ClickHandler

• CloseHandler ...