How do I know when I've stopped scrolling?

How do I know when I've stopped scrolling using Javascript?

Answers:

Answer

You can add an event handler for the scroll event and start a timeout. Something like:

var timer = null;
window.addEventListener('scroll', function() {
    if(timer !== null) {
        clearTimeout(timer);        
    }
    timer = setTimeout(function() {
          // do something
    }, 150);
}, false);

This will start a timeout and wait 150ms. If a new scroll event occurred in the meantime, the timer is aborted and a new one is created. If not, the function will be executed. You probably have to adjust the timing.

Also note that IE uses a different way to attach event listeners, this should give a good introduction: quirksmode - Advanced event registration models

Answer

There isn't a "Stopped Scrolling" event. If you want to do something after the user has finished scrolling, you can set a timer in the "OnScroll" event. If you get another "OnScroll" event fired then reset the timer. When the timer finally does fire, then you can assume the scrolling has stopped. I would think 500 milliseconds would be a good duration to start with.

Here's some sample code that works in IE and Chrome:

<html>
<body onscroll="bodyScroll();">

<script language="javascript">
    var scrollTimer = -1;

    function bodyScroll() {
        document.body.style.backgroundColor = "white";

        if (scrollTimer != -1)
            clearTimeout(scrollTimer);

        scrollTimer = window.setTimeout("scrollFinished()", 500);
    }

    function scrollFinished() {
        document.body.style.backgroundColor = "red";
    }
</script>

<div style="height:2000px;">
Scroll the page down.  The page will turn red when the scrolling has finished.
</div>

</body>
</html>
Answer

I did something like this:

var scrollEvents = (function(document, $){

    var d = {
        scrolling: false,
        scrollDirection : 'none',
        scrollTop: 0,
        eventRegister: {
            scroll: [],
            scrollToTop: [],
            scrollToBottom: [],
            scrollStarted: [],
            scrollStopped: [],
            scrollToTopStarted: [],
            scrollToBottomStarted: []
        },
        getScrollTop: function(){ 
            return d.scrollTop;
        },
        setScrollTop: function(y){
            d.scrollTop = y;
        },
        isScrolling: function(){
            return d.scrolling;
        },
        setScrolling: function(bool){
            var oldVal = d.isScrolling();
            d.scrolling = bool;
            if(bool){
                d.executeCallbacks('scroll');
                if(oldVal !== bool){
                    d.executeCallbacks('scrollStarted');
                }
            }else{
                d.executeCallbacks('scrollStopped');
            }
        },
        getScrollDirection : function(){
            return d.scrollDirection;
        },
        setScrollDirection : function(direction){
            var oldDirection = d.getScrollDirection();
            d.scrollDirection = direction;
            if(direction === 'UP'){
                d.executeCallbacks('scrollToTop');
                if(direction !== oldDirection){
                    d.executeCallbacks('scrollToTopStarted');
                }
            }else if(direction === 'DOWN'){
                d.executeCallbacks('scrollToBottom');
                if(direction !== oldDirection){
                    d.executeCallbacks('scrollToBottomStarted');
                }
            }
        },
        init : function(){
            d.setScrollTop($(document).scrollTop());
            var timer = null;
            $(window).scroll(function(){
                d.setScrolling(true);
                var x = d.getScrollTop();
                setTimeout(function(){
                    var y = $(document).scrollTop();
                    d.setScrollTop(y);
                    if(x > y){
                        d.setScrollDirection('UP');
                    }else{
                        d.setScrollDirection('DOWN');
                    }
                }, 100);
                if(timer !== 'undefined' && timer !== null){
                    clearTimeout(timer);
                }
                timer = setTimeout(function(){
                    d.setScrolling(false);
                    d.setScrollDirection('NONE');
                }, 200);
            });
        },
        registerEvents : function(eventName, callback){
            if(typeof eventName !== 'undefined' && typeof callback === 'function' && typeof d.eventRegister[eventName] !== 'undefined'){
                d.eventRegister[eventName].push(callback);
            }
        },
        executeCallbacks: function(eventName){
            var callabacks = d.eventRegister[eventName];
            for(var k in callabacks){
                if(callabacks.hasOwnProperty(k)){
                    callabacks[k](d.getScrollTop());
                }
            }
        }
    };
    return d;

})(document, $);

the code is available here: documentScrollEvents

Answer

Minor update in your answer. Use mouseover and out function.

 $(document).ready(function() {
           function ticker() {
    $('#ticker li:first').slideUp(function() {
        $(this).appendTo($('#ticker')).slideDown();
    });
}

var ticke= setInterval(function(){ 
                            ticker(); 
            }, 3000);
       $('#ticker li').mouseover(function() { 
          clearInterval(ticke);
      }).mouseout(function() { 
          ticke= setInterval(function(){ ticker(); }, 3000);
        });

        });

DEMO

Answer

I was trying too add a display:block property for social icons that was previously hidden on scroll event and then again hide after 2seconds. But

I too had a same problem as my code for timeout after first scroll would start automatically and did not had reset timeout idea. As it didn't had proper reset function.But after I saw David's idea on this question I was able to reset timeout even if someone again scrolled before actually completing previous timeout.

  1. problem code shown below before solving

    $(window).scroll(function(){
      setTimeout(function(){
         $('.fixed-class').slideUp('slow');
       },2000);
    });
    

  1. edited and working code with reset timer if next scroll occurs before 2s

    var timer=null;
    $(window).scroll(function(){
       $('.fixed-class').css("display", "block");
       if(timer !== null) {
          clearTimeout(timer);
    } timer=setTimeout(function(){ $('.fixed-class').slideUp('slow'); },2000);

    });

My working code will trigger a hidden division of class named 'fixed-class' to show in block on every scroll. From start of latest scroll the timer will count 2 sec and then again change the display from block to hidden.

Answer
(function( $ ) {
        $(function() {
            var $output = $( "#output" ),
                scrolling = "<span id='scrolling'>Scrolling</span>",
                stopped = "<span id='stopped'>Stopped</span>";
                $( window ).scroll(function() {
                    $output.html( scrolling );
                    clearTimeout( $.data( this, "scrollCheck" ) );
                    $.data( this, "scrollCheck", setTimeout(function() {
                        $output.html( stopped );
                    }, 250) );

                });
        });
    })( jQuery );

=======>>>> Working Example here

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