This example shows a way to show target lines in a bar chart, by use of its second plot, of type point.
In the second plot, the dot's shape is changed to bar, and then it is rotated, making it look like target lines.
Modified http://www.webdetails.pt/ctools/charts/lib/jquery.tipsy.js to a secure url
Modified http://www.webdetails.pt/ctools/charts/lib/protovis.js to a secure url
Modified http://www.webdetails.pt/ctools/charts/lib/protovis-msie.js to a secure url
Modified http://www.webdetails.pt/ctools/charts/lib/tipsy.js to a secure url
Modified http://www.webdetails.pt/ctools/charts/lib/def.js to a secure url
Modified http://www.webdetails.pt/ctools/charts/lib/pvc-r2.0.js to a secure url
https://ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.min.js
https://www.webdetails.pt/ctools/charts/lib/jquery.tipsy.js
https://www.webdetails.pt/ctools/charts/lib/protovis.js
https://www.webdetails.pt/ctools/charts/lib/protovis-msie.js
https://www.webdetails.pt/ctools/charts/lib/tipsy.js
https://www.webdetails.pt/ctools/charts/lib/def.js
https://www.webdetails.pt/ctools/charts/lib/pvc-r2.0.js