With a few steps you can enable alternate background colors on the grid.
The background color should be generated by the function depending on the row order in the grid.
var alternate = function(){ return this.getProperty("row/order") % 2 ? "threedface" : "white"; }
Then you need to create a new row template.
var row = new Active.Templates.Row;
Assign a color function to the background color style.
row.setStyle("background", alternate);
An use this modified row template instead of standard one.
obj.setTemplate("row", row);
Complete example: