You can use jquery
If you want to add a click event to a slice:
// this adds a click event to the first slice
$("path[data-id='s0']").click(function() {
alert('you clicked slice one');
});
// if you have multiple pie's you can be more specific
$("#svg svg path[data-id='s0']").click(function(){
alert('you just clicked pie with id #svg');
});
if you want to add a click event to the whole pie:
$('#svg').click(function(e){
alert('you just clicked the whole pie!');
});