Detect whether scroll event was created by user

Unfortunately, there is no direct way of telling that.

I would say if you can redesign your app so that it doesn’t depend on this type of flow, go for that.

If not, a workaround I can think of is to keep track of user initiated scrolls and check that to see if the scroll was triggered by the browser or by the user.

Here’s an example that I put together which does this pretty well (except for browsers where jQuery history has problems with).

You need to run this locally to be able to test it fully (jsFiddle/jsbin are not good fits as they iFrame the contents).

Here’s the test cases that I validated:

Page loads – userScroll is false
Scroll using mouse/keyboard – userScroll becomes true
Click on the link to jump to page bottom – userScroll becomes false
Click Back/Forward – userScroll becomes false;

<!DOCTYPE html> 
<html lang="en"> 
<head> 
    <meta charset="utf-8" /> 
    <script src="http://code.jquery.com/jquery-1.6.1.min.js"></script> 
    <script type="text/javascript" src="https://raw.github.com/tkyk/jquery-history-plugin/master/jquery.history.js"></script> 
</head> 
<body> 
    <span> hello there </span><br/> 
    <a href="#bottom"> click here to go down </a> 
    <br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/> 
    <br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/> 
    <br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/> 
    <br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/> 
    <br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/> 
    <br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/> 
    <br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/><br/> 
    <a name="bottom"> just sitting </a> 
</body> 
<script type="text/javascript"> 

var userScroll = false;     

function mouseEvent(e) { 
    userScroll = true; 
} 


$(function() { 

    // reset flag on back/forward 
    $.history.init(function(hash){ 
        userScroll = false; 
    }); 

    $(document).keydown(function(e) { 
        if(e.which == 33        // page up 
           || e.which == 34     // page dn 
           || e.which == 32     // spacebar
           || e.which == 38     // up 
           || e.which == 40     // down 
           || (e.ctrlKey && e.which == 36)     // ctrl + home 
           || (e.ctrlKey && e.which == 35)     // ctrl + end 
          ) { 
            userScroll = true; 
        } 
    }); 

    // detect user scroll through mouse
    // Mozilla/Webkit 
    if(window.addEventListener) {
        document.addEventListener('DOMMouseScroll', mouseEvent, false); 
    }

    //for IE/OPERA etc 
    document.onmousewheel = mouseEvent; 


    // to reset flag when named anchors are clicked
    $('a[href*=#]').click(function() { 
        userScroll = false;
    }); 

      // detect browser/user scroll
    $(document).scroll( function(){  
        console.log('Scroll initiated by ' + (userScroll == true ? "user" : "browser"));
    });
}); 
</script> 
</html>

Notes:

This doesn’t track scrolling when the user drags the scrollbar with mouse. This can be added with some more code, which I left as an exercise for you.
event.keyCodes may vary by OS, so you may have to change that appropriately.

Hope this helps!

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