Pre-Order Your HTML5 Application Development INF-306

The correct answers are A and C because background-size: contain and background-size: cover are the CSS values that scale a background image in response to the size of the element or viewport. contain scales the background image as large as possible while preserving the entire image inside the background area. This prevents cropping and maintains the image’s aspect ratio, although empty space may appear if the container and image proportions differ. cover also preserves the aspect ratio, but scales the image until the entire background area is filled; this may crop part of the image, but it prevents empty space. Both values are commonly used in responsive design because the image automatically recalculates its rendered size as the page or element changes dimensions. initial resets the property to its default behavior and does not intentionally create responsive scaling. auto uses the image’s intrinsic dimensions or proportional automatic sizing, so it does not reliably adjust the graphic to different screen sizes in the way required. References/topics: responsive design, CSS background images, background-size, contain, cover, viewport-based scaling.

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The correct method is preventDefault(). During form submission, the browser’s default behavior is to submit the form to the target URL, which may navigate away from the current page or reload it. If the submitted data is invalid and the application must display custom error messages while preserving the entered values, the submit event handler should call event.preventDefault(). This cancels the default submit action, allowing the page to remain in place and the script to display validation feedback next to the relevant form controls. defaultPrevented is not the method to use; it is only a Boolean property that indicates whether preventDefault() has already been called. cancelable is also only informational; it tells whether the event’s default behavior can be canceled. abort is unrelated to form validation and does not provide the required control over form submission. References/topics: HTML5 form validation, custom validation messages, submit event, event cancellation, preserving form data.

First drop-down: datalist

Second drop-down: vehicles

Third drop-down: < /datalist >

The correct element is < datalist > because the interface requires a text input that provides selectable suggestions while still allowing the user to type. The < input > element uses list= " vehicles " , so it must be connected to a < datalist > element whose id is exactly vehicles. The id cannot be vehicle, because vehicle is already the input element’s own identifier and does not match the value used by the list attribute. The < option > elements inside the datalist define the suggested values: Motorcycle, Truck, Boat, Car, and Bicycle. ul, ol, and li are list-markup elements and do not create input suggestions. select would create a fixed dropdown list, but it would not match the editable input-with-suggestions behavior shown. The closing tag must match the opening datalist element, so the final selection is < /datalist > .