To get the querystring of the href attribute of an area, use the search property. You can try to run the following code to search the querystring −
Example
<!DOCTYPE html>
<html>
<body>
<img 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 x = document.getElementById("myarea").search;
document.write("<br>Querystring: "+x);
</script>
</body>
</html>