Check if a user has scrolled to the bottom

716

votes

I'm making a pagination system (sort of like Facebook) where the content loads when the user scrolls to the bottom. I imagine the best way to do that is to find when the user is at the bottom of the page and run an ajax query to load more posts.

The only problem is I don't know how to check if the user has scrolled to the bottom of the page with jQuery. Any ideas?

I need to find a way to check when the user has scrolled to the bottom of the page with jQuery.

javascriptjqueryscrollpagination

That's funny, I'm trying to figure out which function is being called when I scroll to the bottom, so I can block this infuriating "feature". – endolith

For a React.js solution, this link might help: stackoverflow.com/a/53158893/4265546 – raksheetbhat

1077

votes

Use the .scroll() event on window, like this:

$(window).scroll(function() {
   if($(window).scrollTop() + $(window).height() == $(document).height()) {
       alert("bottom!");
   }
});

You can test it here, this takes the top scroll of the window, so how much it's scrolled down, adds the height of the visible window and checks if that equals the height of the overall content (document). If you wanted to instead check if the user is near the bottom, it'd look something like this:

$(window).scroll(function() {
   if($(window).scrollTop() + $(window).height() > $(document).height() - 100) {
       alert("near bottom!");
   }
});

You can test that version here, just adjust that 100 to whatever pixel from the bottom you want to trigger on.

135

votes

I'm not exactly sure why this has not been posted yet, but as per the documentation from MDN, the simplest way is by using native javascript properties:

element.scrollHeight - element.scrollTop === element.clientHeight

Returns true when you're at the bottom of any scrollable element. So simply using javascript:

element.addEventListener('scroll', function(event)
{
    var element = event.target;
    if (element.scrollHeight - element.scrollTop === element.clientHeight)
    {
        console.log('scrolled');
    }
});

scrollHeight have wide support in browsers, from ie 8 to be more precise, while clientHeight and scrollTop are both supported by everyone. Even ie 6. This should be cross browser safe.

123

votes

Nick Craver's answer works fine, spare the issue that the value of $(document).height() varies by browser.

To make it work on all browsers, use this function from James Padolsey:

function getDocHeight() {
    var D = document;
    return Math.max(
        D.body.scrollHeight, D.documentElement.scrollHeight,
        D.body.offsetHeight, D.documentElement.offsetHeight,
        D.body.clientHeight, D.documentElement.clientHeight
    );
}

in place of $(document).height(), so that the final code is:

$(window).scroll(function() {
       if($(window).scrollTop() + $(window).height() == getDocHeight()) {
           alert("bottom!");
       }
   });

54

votes

For those using Nick's solution and getting repeated alerts / events firing, you could add a line of code above the alert example:

$(window).scroll(function() {
   if($(window).scrollTop() + $(window).height() > $(document).height() - 100) {
       $(window).unbind('scroll');
       alert("near bottom!");
   }
});

This means that the code will only fire the first time you're within 100px of the bottom of the document. It won't repeat if you scroll back up and then back down, which may or may not be useful depending on what you're using Nick's code for.

40

votes

Further to the excellent accepted answer from Nick Craver, you can throttle the scroll event so that it is not fired so frequently thus increasing browser performance:

var _throttleTimer = null;
var _throttleDelay = 100;
var $window = $(window);
var $document = $(document);

$document.ready(function () {

    $window
        .off('scroll', ScrollHandler)
        .on('scroll', ScrollHandler);

});

function ScrollHandler(e) {
    //throttle event:
    clearTimeout(_throttleTimer);
    _throttleTimer = setTimeout(function () {
        console.log('scroll');

        //do work
        if ($window.scrollTop() + $window.height() > $document.height() - 100) {
            alert("near bottom!");
        }

    }, _throttleDelay);
}

37

votes

Nick Craver's answer needs to be slightly modified to work on iOS 6 Safari Mobile and should be:

$(window).scroll(function() {
   if($(window).scrollTop() + window.innerHeight == $(document).height()) {
       alert("bottom!");
   }
});

Changing $(window).height() to window.innerHeight should be done because when the address bar is hidden an additional 60px are added to the window's height but using $(window).height() does not reflect this change, while using window.innerHeight does.

Note: The window.innerHeight property also includes the horizontal scrollbar's height (if it is rendered), unlike $(window).height() which will not include the horizontal scrollbar's height. This is not a problem in Mobile Safari, but could cause unexpected behavior in other browsers or future versions of Mobile Safari. Changing == to >= could fix this for most common use cases.

Read more about the window.innerHeight property here

25

votes

Here's a fairly simple approach

const didScrollToBottom = elm.scrollTop + elm.clientHeight == elm.scrollHeight

Example

elm.onscroll = function() {
    if(elm.scrollTop + elm.clientHeight == elm.scrollHeight) {
        // User has scrolled to the bottom of the element
    }
}

Where elm is an element retrieved from i.e document.getElementById.

18

votes

Please check this answer

 window.onscroll = function(ev) {
    if ((window.innerHeight + window.scrollY) >= document.body.offsetHeight) {
       console.log("bottom");
    }
};

You can do footerHeight - document.body.offsetHeight to see if you are near the footer or reached the footer

17

votes

Here is a piece of code that will help you debug your code, I tested the above answers and found them to be buggy. I have test the followings on Chrome, IE, Firefox, IPad(Safari). I don't have any others installed to test...

<script type="text/javascript">
   $(function() {
      $(window).scroll(function () {
         var docElement = $(document)[0].documentElement;
         var winElement = $(window)[0];

         if ((docElement.scrollHeight - winElement.innerHeight) == winElement.pageYOffset) {
            alert('bottom');
         }
      });
   });
</script>

There may be a simpler solution, but I stopped at the point at which IT WORKED

If you are still having problems with some rogue browser, here is some code to help you debug:

<script type="text/javascript">
   $(function() {
      $(window).scroll(function () {
         var docElement = $(document)[0].documentElement;
         var details = "";
         details += '<b>Document</b><br />';
         details += 'clientHeight:' + docElement.clientHeight + '<br />';
         details += 'clientTop:' + docElement.clientTop + '<br />';
         details += 'offsetHeight:' + docElement.offsetHeight + '<br />';
         details += 'offsetParent:' + (docElement.offsetParent == null) + '<br />';
         details += 'scrollHeight:' + docElement.scrollHeight + '<br />';
         details += 'scrollTop:' + docElement.scrollTop + '<br />';

         var winElement = $(window)[0];
         details += '<b>Window</b><br />';
         details += 'innerHeight:' + winElement.innerHeight + '<br />';
         details += 'outerHeight:' + winElement.outerHeight + '<br />';
         details += 'pageYOffset:' + winElement.pageYOffset + '<br />';
         details += 'screenTop:' + winElement.screenTop + '<br />';
         details += 'screenY:' + winElement.screenY + '<br />';
         details += 'scrollY:' + winElement.scrollY + '<br />';

         details += '<b>End of page</b><br />';
         details += 'Test:' + (docElement.scrollHeight - winElement.innerHeight) + '=' + winElement.pageYOffset + '<br />';
         details += 'End of Page? ';
         if ((docElement.scrollHeight - winElement.innerHeight) == winElement.pageYOffset) {
             details += 'YES';
         } else {
             details += 'NO';
         }

         $('#test').html(details);
      });
   });
</script>
<div id="test" style="position: fixed; left:0; top: 0; z-index: 9999; background-color: #FFFFFF;">

I hope this will save someone some time.

12

votes

var elemScrolPosition = elem.scrollHeight - elem.scrollTop - elem.clientHeight;

It calculates distance scroll bar to bottom of element. Equal 0, if scroll bar has reached bottom.

11

votes

This is my two cents:

$('#container_element').scroll( function(){
        console.log($(this).scrollTop()+' + '+ $(this).height()+' = '+ ($(this).scrollTop() + $(this).height())   +' _ '+ $(this)[0].scrollHeight  );
        if($(this).scrollTop() + $(this).height() == $(this)[0].scrollHeight){
            console.log('bottom found');
        }
    });

6

votes

Pure JS with cross-browser and debouncing (Pretty good performance)

var CheckIfScrollBottom = debouncer(function() {
    if(getDocHeight() == getScrollXY()[1] + window.innerHeight) {
       console.log('Bottom!');
    }
},500);

document.addEventListener('scroll',CheckIfScrollBottom);

function debouncer(a,b,c){var d;return function(){var e=this,f=arguments,g=function(){d=null,c||a.apply(e,f)},h=c&&!d;clearTimeout(d),d=setTimeout(g,b),h&&a.apply(e,f)}}
function getScrollXY(){var a=0,b=0;return"number"==typeof window.pageYOffset?(b=window.pageYOffset,a=window.pageXOffset):document.body&&(document.body.scrollLeft||document.body.scrollTop)?(b=document.body.scrollTop,a=document.body.scrollLeft):document.documentElement&&(document.documentElement.scrollLeft||document.documentElement.scrollTop)&&(b=document.documentElement.scrollTop,a=document.documentElement.scrollLeft),[a,b]}
function getDocHeight(){var a=document;return Math.max(a.body.scrollHeight,a.documentElement.scrollHeight,a.body.offsetHeight,a.documentElement.offsetHeight,a.body.clientHeight,a.documentElement.clientHeight)}

Demo : http://jsbin.com/geherovena/edit?js,output

PS: Debouncer, getScrollXY, getDocHeight not written by me

I just show how its work, And how I will do

6

votes

My solution in plain js:

let el=document.getElementById('el');
el.addEventListener('scroll', function(e) {
    if (this.scrollHeight - this.scrollTop - this.clientHeight<=0) {
        alert('Bottom');
    }
});

#el{
  width:400px;
  height:100px;
  overflow-y:scroll;
}

<div id="el">
<div>content</div>
<div>content</div>
<div>content</div>
<div>content</div>
<div>content</div>
<div>content</div>
<div>content</div>
<div>content</div>
<div>content</div>
<div>content</div>
<div>content</div>
</div>

4

votes

Try this for match condition if scroll to bottom end

if ($(this)[0].scrollHeight - $(this).scrollTop() == 
    $(this).outerHeight()) {

    //code for your custom logic

}

3

votes

Nick answers its fine but you will have functions which repeats itsself while scrolling or will not work at all if user has the window zoomed. I came up with an easy fix just math.round the first height and it works just as assumed.

    if (Math.round($(window).scrollTop()) + $(window).innerHeight() == $(document).height()){
    loadPagination();
    $(".go-up").css("display","block").show("slow");
}

3

votes

You can try the following code,

$("#dashboard-scroll").scroll(function(){
    var ele = document.getElementById('dashboard-scroll');
    if(ele.scrollHeight - ele.scrollTop === ele.clientHeight){
       console.log('at the bottom of the scroll');
    }
});

3

votes

Instead of listening to the scroll event, using Intersection Observer is the inexpensive one for checking if the last element was visible on the viewport (that's mean user was scrolled to the bottom). It also supported for IE7 with the polyfill.

var observer = new IntersectionObserver(function(entries){
   if(entries[0].isIntersecting === true)
      console.log("Scrolled to the bottom");
   else
      console.log("Not on the bottom");
}, {
   root:document.querySelector('#scrollContainer'),
   threshold:1 // Trigger only when whole element was visible
});

observer.observe(document.querySelector('#scrollContainer').lastElementChild);

#scrollContainer{
  height: 100px;
  overflow: hidden scroll;
}

<div id="scrollContainer">
  <div>Item 1</div>
  <div>Item 2</div>
  <div>Item 3</div>
  <div>Item 4</div>
  <div>Item 5</div>
  <div>Item 6</div>
  <div>Item 7</div>
  <div>Item 8</div>
  <div>Item 9</div>
  <div>Item 10</div>
</div>

2

votes

This gives accurate results, when checking on a scrollable element (i.e. not window):

// `element` is a native JS HTMLElement
if ( element.scrollTop == (element.scrollHeight - element.offsetHeight) )
    // Element scrolled to bottom

offsetHeight should give the actual visible height of an element (including padding, margin, and scrollbars), and scrollHeight is the entire height of an element including invisible (overflowed) areas.

jQuery's .outerHeight() should give similar result to JS's .offsetHeight -- the documentation in MDN for offsetHeight is unclear about its cross-browser support. To cover more options, this is more complete:

var offsetHeight = ( container.offsetHeight ? container.offsetHeight : $(container).outerHeight() );
if  ( container.scrollTop == (container.scrollHeight - offsetHeight) ) {
   // scrolled to bottom
}

2

votes

In case someone wants a vanilla JS solution and needs to detect when a used has scrolled to the bottom of a <div> I managed to implement it by using these lines of code

window.addEventListener("scroll", () => {
    var offset = element.getBoundingClientRect().top - element.offsetParent.getBoundingClientRect().top;
    const top = window.pageYOffset + window.innerHeight - offset;

    if (top === element.scrollHeight) {
        console.log("bottom");
    }
}, { passive: false });

1

votes

All these solutions doesn't work for me on Firefox and Chrome, so I use custom functions from Miles O'Keefe and meder omuraliev like this:

function getDocHeight()
{
    var D = document;
    return Math.max(
        D.body.scrollHeight, D.documentElement.scrollHeight,
        D.body.offsetHeight, D.documentElement.offsetHeight,
        D.body.clientHeight, D.documentElement.clientHeight
    );
}

function getWindowSize()
{
  var myWidth = 0, myHeight = 0;
  if( typeof( window.innerWidth ) == 'number' ) {
    //Non-IE
    myWidth = window.innerWidth;
    myHeight = window.innerHeight;
  } else if( document.documentElement && ( document.documentElement.clientWidth || document.documentElement.clientHeight ) ) {
    //IE 6+ in 'standards compliant mode'
    myWidth = document.documentElement.clientWidth;
    myHeight = document.documentElement.clientHeight;
  } else if( document.body && ( document.body.clientWidth || document.body.clientHeight ) ) {
    //IE 4 compatible
    myWidth = document.body.clientWidth;
    myHeight = document.body.clientHeight;
  }
  return [myWidth, myHeight];
}

$(window).scroll(function()
{
    if($(window).scrollTop() + getWindowSize()[1] == getDocHeight())
    {
        alert("bottom!");
    }
});

1

votes

Here's my two cents as the accepted answer didn't work for me.

var documentAtBottom = (document.documentElement.scrollTop + window.innerHeight) >= document.documentElement.scrollHeight;

1

votes

Many other solutions doesn't work for me Because on scroll to bottom my div was triggering the alert 2 times and when moving up it was also trigerring upto a few pixels so The solution is:

        $('#your-div').on('resize scroll', function()
        {
            if ($(this).scrollTop() +
                $(this).innerHeight() >=
                $(this)[0].scrollHeight + 10) {

                alert('reached bottom!');
            }
        });

0

votes

Let me show approch without JQuery. Simple JS function:

function isVisible(elem) {
  var coords = elem.getBoundingClientRect();
  var topVisible = coords.top > 0 && coords.top < 0;
  var bottomVisible = coords.bottom < shift && coords.bottom > 0;
  return topVisible || bottomVisible;
}

Short example how to use it:

var img = document.getElementById("pic1");
    if (isVisible(img)) { img.style.opacity = "1.00";  }

0

votes

I used @ddanone answear and added Ajax call.

$('#mydiv').on('scroll', function(){
  function infiniScroll(this);
});

function infiniScroll(mydiv){
console.log($(mydiv).scrollTop()+' + '+ $(mydiv).height()+' = '+ ($(mydiv).scrollTop() + $(mydiv).height())   +' _ '+ $(mydiv)[0].scrollHeight  );

if($(mydiv).scrollTop() + $(mydiv).height() == $(mydiv)[0].scrollHeight){
    console.log('bottom found');
    if(!$.active){ //if there is no ajax call active ( last ajax call waiting for results ) do again my ajax call
        myAjaxCall();
    }
}

}

0

votes

To stop repeated alert of Nick's answer

ScrollActivate();

function ScrollActivate() {
    $(window).on("scroll", function () {
        if ($(window).scrollTop() + $(window).height() > $(document).height() - 100) {
            $(window).off("scroll");
            alert("near bottom!");
        }
    });
}

0

votes

Google Chrome gives the full height of the page if you call $(window).height()

Instead, use window.innerHeight to retrieve the height of your window. Necessary check should be:

if($(window).scrollTop() + window.innerHeight > $(document).height() - 50) {
    console.log("reached bottom!");
}

0

votes

Apparently what worked for me was 'body' and not 'window' like this:

$('body').scroll(function() {


 if($('body').scrollTop() + $('body').height() == $(document).height()) {
     //alert at buttom
 }
 });

for cross-browser compatibility use:

  function getheight(){
    var doc = document;
    return  Math.max(
        doc.body.scrollHeight, doc.documentElement.scrollHeight,
        doc.body.offsetHeight, doc.documentElement.offsetHeight,
        doc.body.clientHeight, doc.documentElement.clientHeight

        );
   }

and then instead of $(document).height() call the function getheight()

$('body').scroll(function() {


   if($('body').scrollTop() + $('body').height() == getheight()  ) {
     //alert at bottom
 }
});

for near bottom use:

$('body').scroll(function() {


if($('body').scrollTop() + $('body').height() > getheight() -100 ) {
    //alert near bottom
 }
 });

0

votes

i used this test to detect the scroll reached the bottom: event.target.scrollTop === event.target.scrollHeight - event.target.offsetHeight

0

votes

Safari can scroll past the bottom of the page which was causing a bug in our application. Solve this using >= instead of ===.

container.scrollTop >= container.scrollHeight - container.clientHeight

Check if a user has scrolled to the bottom

29 Answers