Which JavaScript object can trigger the onerror event handler associated with image loading?

• A. Window
• B. Document
• C. Image
• D. Navigator

Answer: (C)

The onerror handler for image loading is attached to the Image object itself. When you create an image (for example, with new Image() or by creating an element) you can assign an onerror function to respond if the image fails to load, such as due to a 404 or network error. The event fires on that Image object, not on the Window, Document, or Navigator, which handle other kinds of errors or events. For example, if you do var img = new Image(); img.onerror = function() { /* handle load failure */ }; img.src = 'nonexistent.jpg'; the onerror function runs when the image can’t be retrieved.