Alternating Row Color with Repeated Headers

Currently, I have repeated headers for lengthy inventories. I would like to have the responses to alternate coloring along with the header for that response.
I have this as my code currently, but this only makes the headers a different color as this is the alternating row.

jQuery("tr.ReadableAlt").css({"background-color":" lightgray"});

Is there a good way to change or add to this code, to get the desired result.