Can You Style a Mouseover on an Image Map Using CSS?

Image maps are used to delineate clickable areas in an image. Styling these areas, which appear by default as plain geometric shapes, can serve as a visually interactive interface. One may wonder if this is feasible with CSS, an indispensable tool for website aesthetics. While CSS cannot directly style image map areas, there are clever workarounds to achieve the desired effect.

CSS-Only Solution:

An alternative to manipulating image maps via CSS is to superimpose clickable elements (for example, blocks) over the image. Placing these elements in precise alignment with map areas, together with opacity adjustments on mouseover, mimics the visual effect of styling the image map itself. This approach simplifies implementation, further leveraging CSS's strong capabilities.

Example:

In this example, two a blocks are positioned absolutely and initially given 0 opacity, rendering them invisible. Upon hovering over these areas, opacity is set to 0.2, revealing a subtle overlay effect. The image remains in the background.