How can we find out scrollbar position has reached at the bottom in js

How can we find out scrollbar position has reached at the bottom in js


How can we find out scrollbar position has reached at the bottom in
jquery?
I have added a div and set an attribute overflow, but I couldn't get
the on scroll functionality for the the particular div's onsroll event
I have given it like this
$('#dir-listing-inner').scroll(function(){
if(Util.isScrollBottom()){
$.ajax({
url: pname.convertURL('front/page'),
success:(function(results){
$("#results").append(results); //correct one
})
});
}
});
<div id="dir-listing-inner">
Blah blah Blah blah Blah blah
Blah blah
Blah blah
Blah blah
Blah blah
</div>
#dir-listing-inner{
width:860px;
height:440px;
overflow-x:hidden;
overflow-y:auto;
}
Can you please help me to sort it out
Thanks in advance..
cheers
joban