Code
function draw(canvasName) {
var canvas = document.getElementById(canvasName);
chart = new Scribl(canvas, 500);
chart.laneSizes = 18;
chart.laneBuffer = 2;
chart.trackBuffer = 40;
chart.glyph.text.color = 'white';
track1 = chart.addTrack();
gene1 = track1.addFeature( new BlockArrow('track1', 5, 750 , '-') );
gene2 = track1.addFeature( new BlockArrow('track1', 3500, 2500, '+') );
gene3 = track1.addFeature( new BlockArrow('track1', 8100, 1000, '-') );
gene4 = track1.addFeature( new BlockArrow('track1', 6200, 1500, '+') );
chart.track1.name = 'track 1';
track2 = chart.addTrack();
gene5 = track2.addFeature( new BlockArrow('track2', 100, 1000, '-') );
gene6 = track2.addFeature( new BlockArrow('track2', 3500, 1500, '-') );
chart.track2.name = 'track 2';
track3Lane1 = chart.addTrack().addLane();
gene7 = track3Lane1.addFeature( new BlockArrow('track3', 2230, 1000, '+') );
gene8 = track3Lane1.addFeature( new BlockArrow('track3',3300, 1500, '+') );
gene9 = track3Lane1.addFeature( new BlockArrow('track3', 4800, 1000, '-') );
chart.track3.name = 'track 3';
chart.draw();
}