looking at how i can highlight a table row after dynamically adding it with jquery my code seems to be adding the row with no problems, but its not highlighting the correct row<
I would assume that the effect would be applied to what ever tr:last was as that is the main selector.
after() returns the jQuery object from the original selector $('#opponents tr:last') allowing you to continue chaining on to that main selector.
DEMO - Using existing code, wrong row is highlighted
Try separating the new row into it's own instead and applying the effect to it directly. Similar to this:
var $newRow = $('data more data ');
$('#opponents tr:last').after($newRow);
$newRow.effect("highlight", {}, 3000);
DEMO - Working DEMO of above code