Setup jQuerify bookmarklet from http://www.learningjquery.com/2008/06/updated-jquery-bookmarklet
Once you have that just place following code in FireBug and you will see alternate style applied J
var itemIndex =0;
jQuery("tr").each(function(){
itemIndex = itemIndex + 1;
if( (itemIndex % 2) === 0){
jQuery(this)
.css("background", "#6b7fde")
.css("color", "#fff");
}
return this;
})
.css("font-size", "12px")
.css("font-family", "verdana")
.attr("valign", "top");
jQuery("table").attr("cellpadding", "4");