oth the Flash   content and the HTML content around it may be keyboard accessible, many browsers do not support moving keyboard focus between the Flash content and HTML   content without using a mouse. Once focus is placed inside the Flash   content, a keyboard user will be trapped there. Similarly, when focus is   placed somewhere else on the HTML content (outside the Flash content), it   will be impossible to move focus into the content.  This technique is designed to let the Flash author address this iss