Google Apps Script, 2nd Edition

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. The only problem is that clicking your “Subscribe” button doesn’t do anything yet. In this chapter, we will add actions to that button to store the visitors’ email addresses, thank them if they entered an email address, and send them an email verification.

Handling User Actions

In order to work, a button needs an event handler. However, buttons are not the only elements that can have handlers, and click is not the only handler type. For example, a text box may have a handler that responds to the user pressing the Enter key, or a listbox sometimes needs to fill a second list for situations like choosing a city after the state has been selected. In such a 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 an element 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 he has clicked, and an additional handler may take care of that detail.

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

Anatomy of a Handler

Google Apps Script allows ...