[Bug 2787] addresses the inconsistent cross-browser behavior regarding the focus order of image maps.
The WC3's reply to [Bug 27787] implies that the current focus behaviors are correct. It compares the relationship of an image and an image map to the relationship between a label and a form control. While labels can be placed anywhere in the DOM, it makes most sense to place them as siblings to the form control they address. Additionally, since having elements with duplicate ID values in the DOM results in invalid HTML, it also makes sense not to re-use a given
map element without assigning it a unique ID value.
See the recommend and non-recommended examples below. Focus order test results are included in each example