10秒后刷新页面中的特定div

I have 2 pages chat.php and allchat.php and I can successfully load allchat.php page in chat.php div after 10 seconds Here is a code

$(document).ready(function(){
        setInterval(function() {
            $("#abc").load("allchat.php");
        }, 10000);
    });

Now If I have a div having id "def" in chat.php and How I do to refresh this div after 10 second. Remember I don't load any otherpage like in above code I try this code but It is not working

$(document).ready(function(){
        setInterval(function() {
            $("#abc").load("chat.php #def");
        }, 10000);
    });

Just like for the div abc you created a separate page i.e. allChat.php similarly for the div def you should also create a separate page say def.php then after 10 sec load this page in exactly same way.