The alert plugin, as we have seen, is exceedingly simple. The alert is rendered on the page, displaying a message, and the only functionality it has is the ability to close and disappear when a user clicks on a certain element.

To demonstrate how to customize or extend a plugin, in this case, alert we will keep it very simple. We will add an extra bit of functionality—when a user clicks on a certain element, the alert will minimize. Similarly, we also want to give the user the ability to expand the alert when it is in its minimized state. To do this, we need to extend both the JavaScript and the styling of alert.

Before we get to the coding of the plugin functionality and styling, let's put together the markup for an alert on the MyPhoto page.