Click event on the stroke of a rectangle

i want to add the click event only on the stroke of the rectangle and avoid the click inside the rectangle.

Here is the code below:

    var stage = new Kinetic.Stage({
    container: 'container',
    width: 578,
    height: 200
});
var layer = new Kinetic.Layer();
 var rect = new Kinetic.Rect({
        x: 239,
        y: 75,
        width: 100,
        height: 50,
        fill: 'green',
        stroke: 'black',
        strokeWidth: 4
      });

rect.on('click', function () {
    var fill = this.getFill() == 'red' ? '#00d00f' : 'red';
    this.setFill(fill);
    layer.draw();
});

layer.add(rect);
stage.add(layer);

and the fiddle : jsfiddle.net/6N3PB/