Visual Basic.NET How to Program (PDF)

Appendix K Introduction to XHTML: Part 2 1447
41
44
45
46
47
50
51
52
53
54
56
57
58
59
Fig. K.7 Image with links anchored to an image map (part 2 of 2).
Lines 19–50 define an image map via a map element. Attribute id (line 19) identifies
the image map. If id is omitted, the map cannot be referenced by an image. Shortly, we
discuss how to reference an image map. Hotspots are defined with area elements (as
shown on lines 24–26). Attribute href (line 24) specifies the link’s target (i.e., the
resource to which to link). Attributes shape (line 24) and coords (line 25) specify the
hotspot’s shape and coordinates, respectively. Attribute alt (line 26) provides alternative
text for the link.
Common Programming Error K.5
Not specifying an id attribute for a map element prevents an img element from using the
map’s area elements to define hotspots. K.5
The markup on lines 24–26 creates a rectangular hotspot (shape = "rect") for the
coordinates specified in the coords attribute. A coordinate pair consists of two numbers