Adapt highlighting of objects

The JavaScript code

Create an invisible divsion:

<div id="myinfobox" 
    style="
        z-Index:99;
        display:none;
        position:absolute; 
        top:0px;
        left:0px;
        background-color:#ffff88;
        padding:10px;
        /* Cross-browser opacity:*/
        -ms-filter:'progid:DXImageTransform.Microsoft.Alpha(Opacity=50)'; 
        filter: alpha(opacity=50);
        opacity:.5;
    "
></div>

// A simple construction, consisting of three points , two lines, one circle.
var brd = JXG.JSXGraph.initBoard('jxgbox', {boundingbox: [-5, 5, 5, -5], grid: false});
var p1 = brd.create('point',[3,0]);
var p2 = brd.create('point',[-1,0]);
var p3 = brd.create('point',[0,4]);
var l1 = brd.create('line',[p1,p2]);
var l2 = brd.create('line',[p1,p3]);

var c = brd.create('circle',[p2,p3]);

// First, we overwrite the highling method for ALL lines
var infobox = document.getElementById('myinfobox');
JXG.Line.prototype.highlight = function(){
    infobox.innerHTML = this.board.mousePosRel.toString();
    infobox.style.left = (this.board.mousePosRel[0]+0)+'px';
    infobox.style.top =  (this.board.mousePosRel[1]+0)+'px';
    infobox.style.display = 'block';
}
JXG.Line.prototype.noHighlight = function(){
    infobox.style.display = 'none';
}

//Second, we overwrite the highlighting method just for the circle c.
c.highlight = function(){
    infobox.innerHTML = this.board.mousePosRel.toString();
    infobox.style.left = (this.board.mousePosRel[0]+0)+'px';
    infobox.style.top =  (this.board.mousePosRel[1]+0)+'px';
    infobox.style.display = 'block';
}
c.noHighlight = function(){
    infobox.style.display = 'none';
}