HTML Tidy accessibility-check 1.0/1.1.9

This file demonstrates an <area> that is missing "alt" text

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
    "http://www.w3.org/TR/html4/loose.dtd">
<html lang="en">
<head>
<title>alert 1.0/1.1.9</title>
</head>
<body>

<map name="imagemap">
  <area shape="poly" coords="185,0,355,0,295,123" href="a.html" alt="Link a" />
  <area shape="poly" coords="336,202,549,203,549" href="b.html" />
  <area shape="rect" coords="0,10,172,20" href="c.html" alt="Service" />
</map>
<img src="imap.jpg" usemap="#imagemap" alt="navigation" longdesc="ld.html" />

</body>
</html>