<div id="display_info" style="visibility:hidden; position: fixed; top: 10px; left: 3px; width: 400px;  background-color: azure; border: 1px solid black; padding:5px">
        description written here by JavaScript
    </div>

    <script type="text/javascript">
        var ps = document.getElementsByTagName("area");
        for (var i = 0; i < ps.length; ++i) {
            ps[i].onmouseover = (function() {
            var ref = this.href.substr(this.href.indexOf("#")+1)
            document.getElementById("display_info").innerHTML = ref;

            var as = document.getElementsByTagName("a");
            for (var i = 0; i < as.length; ++i) {
                if (as[i].name == ref) {
                   var x = as[i]; while (x.tagName.toLowerCase() != "p") {  x = x.nextSibling; }
                   display_info.innerHTML = x.innerHTML;
                   display_info.style.visibility = "visible";
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            });
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    </script>