jQuery: detecting reaching bottom of scroll doesn't work, only detects the top

Question

So basically my problem is a seemingly simple one.

You can see it in action at http://furnace.howcode.com (please note that data is returned via Ajax, so if nothing happens give it a few moments!).

What's MEANT to happen, is in the second column when you reach the bottom of scrolling, the next 5 results are returned.

But what actually happens is it only returns the 5 results when you hit the TOP of the scroll area. Try it: scroll down, nothing happens. Scroll back up to the top, the results are returned.

What's going wrong?

Here's my code I'm using:

$('#col2').scroll(function(){
    if ($('#col2').scrollTop() == $('#col2').height() - $('#col2').height()){
       loadMore();
    }
});

loadMore(); is the function that gets the data and appends it.

So what's going wrong here? Thanks for your help!

Kay

I'm afraid nothing is working. Does anybody have any further ideas? – Kay

Answer 1

Your math is wrong, your saying if the scrollbar position is equal to the height of the column minus the height of the column (which equals zero) load more. that's why your loadMore() is called at the top of your col.

Try:

$('#col2').scroll(function(){
    if ($('#col2').scrollTop() == $('#col2').height()){
       loadMore();
    }
});

Traps

I'm afraid this doesn't work. I've copy-pasted it after typing it in manually, but, nothing happens. The original URL I got the original source from was this: webresourcesdepot.com/load-content-while-scrolling-with-jquery – Kay

Answer 2

The following has been tested, and works fine:

$(window).scroll(function() {
  if ($(window).scrollTop() == $(document).height() - $(window).height()) {
    loadMore();
  }
});

Bootery

It may be handy to wrap the function in a debounce function, to improve performance. – Checkroom

Answer 3

This has worked for me in the past.

var col = $('#col2');
col.scroll(function(){
   if (col.outerHeight() == (col.get(0).scrollHeight - col.scrollTop()))
       loadMore(); 
});

Here's a good explanation too.

Smart

I've looked at the explanation and tried out your example - but nothing happens. I really can't fathom out why. Any further ideas? – Kay

@Kay Webb-Heller - I can fathom why. I missed something kind of important. scrollHeight can't be used on the jquery object. you need to specify col[0].scrollHeight in order for it to work. I edited the answer to include that – Smart

col.get(0).scrollHeight is a more appropriate jQuery way to deal with it – Smart

Pretty much works for me, but there is a problem if there is also a horizontal scrollbar. A hackish fix: if( col.outerHeight()+20 >= (col.get(0).scrollHeight - col.scrollTop()) )... – Apostate

Answer 4

I found an alternative that works.

None of these answers worked for me (currently testing in FireFox 22.0), and after a lot of research I found, what seems to be, a much cleaner and straight forward solution.

Implemented solution:

function IsScrollbarAtBottom() {
    var documentHeight = $(document).height();
    var scrollDifference = $(window).height() + $(window).scrollTop();
    return (documentHeight == scrollDifference);
}

Resource: http://jquery.10927.n7.nabble.com/How-can-we-find-out-scrollbar-position-has-reached-at-the-bottom-in-js-td145336.html

Regards

Comforter

Answer 5

The solution that jordanstephens posted is on the right track. However, what you need is not the height of #col2, you need the height of the parent element of #col2.

Example:

$('#col2').scroll(function(){
  if ($('#col2').scrollTop() == $('#col2').parent().height()) {
    loadMore();
  }
}

Godred

The parent element is basically $(document), #col2 is a top-level tag. I've tried this but still no luck. I can't really say much... as nothing happens! :S – Kay

if the parent is the document, then instead of $('#col2').parent().height() just use $(window).height() – Godred

Answer 6

Maybe the following will work:

1. HTML - wrap whatever is inside #col2 with another DIV, say #col2-inner
2. CSS - set a fixed height and 'overflow: auto' only for #col2

3. JS - see plugin below:

   $.fn.scrollPaging = function (handler) {
       return this.each(function () {
           var $this = $(this),
               $inner = $this.children().first();
   
           $this.scroll(function (event) {
               var scrollBottom = $this.scrollTop() + $this.height(),
                   totalScroll = $inner.height();
   
               if (scrollBottom >= totalScroll) {
                   handler();
               }
           });
   
       });
   };
   
   $('#col2').scrollPaging(loadMore);
   

National

Answer 7

@munch was closest, but if you have a border on the element, then you need to use .innerHeight() instead of .outerHeight() since the latter includes the border and .scrollTop() does not (.height() is also out if you have padding). Also, at least as of jQuery 1.7.1 and maybe earlier, I'd recommend using .prop('scrollHeight') instead of retrieving it directly from the DOM. I found some talk that the DOM scrollHeight is broken on IE 5-8 and the jQuery function abstracts that for me, at least on IE8.

var $col = $('#col2');
$col.scroll(function(){
if ($col.innerHeight() == $col.prop('scrollHeight') - $col.scrollTop())
    loadMore(); 
});

Turkic

Answer 8

I know this question is already solved, but a concern when using jQuery scrollTOp() function on element other than on $(window).scrollTop() or $(document).scrollTop() since some issue like

jQuery: detecting reaching bottom of scroll doesn't work, only detects the top

Explain why scrollTop() always returns 0 here

$(document).scrollTop() always returns 0

So you can use

$(window).scrollTop() - $('your_selector').offset().top 

instead of

$('your_selector').scrollTOp() 

to avoid the jQuery scrollTOp() issue.

My suggestion is as follows:

   $(window).scroll(function() {
       var $more = $('#col2');
       var top = $(window).scrollTop() - $more.offset().top;
       if(top + $more.innerHeight() >= $more[0].scrollHeight) {
          loadMore();
       }
   });

Selfrising