how to mouse hover svg
<svg width="500" height="500">
<circle id="circle1" cx="50" cy="50" r="20" fill="red"/>
<circle id="circle2" cx="150" cy="50" r="20" fill="green"/>
</svg>
...
document.getElementById('circle2').addEventListener('click', function(e) {
e.currentTarget.setAttribute('fill', '#ff00cc');
});