The inline HTML in the book references the functions upload_image_error, upload_error_message, and upload_error_to_string. They are not defined else where in the book, but there is a definition in the example code zip file.
The inline HTML in the book references the functions upload_image_error, upload_error_message, and upload_error_to_string. They are not defined else where in the book, but there is a definition in the example code zip file.