为什么不能只突出新数据呢？

I have a refreshing function which checks fresh data in the database every 60 seconds and, if found, adds it to the list.

I want it to be highlighted for a few seconds when it brings it on auto-refresh, yet it does nothing. It either highlights all the list, or nothing!

function clock(){
    $.ajax({
        url: "update.php",
        data: "row=" + num,
        cache: false,  
        success: function(data){ 
            $("#ads").prepend(data);
            $(data).effect('highlight', {}, 5000);
        }
    });
}
setInterval(clock, 60000);

What am I doing wrong?

This selector $(data) doesn't make sense when you use it a second time. It creates a clone since data is not a selector, but (I'm guessing a string of HTML). You should instead only create one copy of your data, and add the effect to it:

$(data).prependTo('#ads').effect('highlight', {}, 5000);

Example JSFiddle post

First data contains the rows you want to prepend. And in the second line $(data) should be the html items that contain that data? What if you prepend the data and give those lines a class that allows you to find those rose and give them a effect?