Adding gridlines to gRaphael line chart

HTML

<script src="http://blog.fruitsoftware.com/wp-content/raphaeljs/raphael-min.js"></script>
<script src="http://blog.fruitsoftware.com/wp-content/raphaeljs/g.raphael-min.js"></script>
<script src="http://blog.fruitsoftware.com/wp-content/raphaeljs/g.line-min.js"></script>
<div id="graph"></div>

JavaScript

var r = Raphael('graph');
var x = 50;
var y = 20;
var w = 400;
var h = 200;
var g = r.linechart(x, y, // top left position
                    w, h, // bottom right position
                    [0, 20], // x values
                    [0, 100], // y values
                    {
                        axis : '0 0 1 1'
                    });
for (var i = 0; i < g.axis[1].text.items.length; i++) {
    r.path(['M', x, g.axis[1].text.items[i].attrs.y, 'H', w + x]).attr({
        stroke : '#EEE'
    }).toBack();
}