This image contains a button and 4 instances of an HTML input element.
In the first instance, the text inside the input box is plain.
In the second instance, the text inside the input box is in italics.
In the third instance, the text inside the input box is in bold and italics.
In the fourth instance, the text inside the input box is in bold and italics and is colored pink.
The image also contains the following explanation text: The HTML input element uses :class attribute binding with an observable Array that gets updated with additional CSS classes. Click the button to add a new class to the class array on the HTML input element.