To get the value of the usemap attribute of a link in JavaScript, use the useMap property. The usemap attribute is used to tell that the document is html (text/html) or css (text/css), etc.
Client-side image maps are enabled by the usemap attribute for the <img /> tag and defined by special <map> and <area> extension tags. The image that is going to form the map is inserted into the page using the <img /> element as normal, except that it carries an extra attribute called usemap.
Example
You can try to run the following code to get the value of the usemap attribute of a link −
<!DOCTYPE html>
<html>
<body>
<img id="myid" src = "/images/html.gif" alt = "HTML Map" border = "0" usemap = "#html"/>
<map name = "html">
<area id="myarea" shape = "circle" coords = "154,150,59" href = "about.htm?id=company" alt = "Team" target = "_self" >
</map>
<script>
var myVal = document.getElementById("myid").useMap;
document.write("<br>Usemap value: "+myVal);
</script>
</body>
</html>