Prevent scrolling of parent element when inner ele

2018-12-31 19:45发布

站内问答 / JavaScript
1976 30 4

I have a little "floating tool box" - a div with position:fixed; overflow:auto. Works just fine.

But when scrolling inside that box (with the mouse wheel) and reaching the bottom OR top, the parent element "takes over" the "scroll request" : The document behind the tool box scrolls.
- Which is annoying and not what the user "asked for".

I'm using jQuery and thought I could stop this behaviour with event.stoppropagation():
$("#toolBox").scroll( function(event){ event.stoppropagation() });

It does enter the function, but still, propagation happens anyway (the document scrolls)
- It's surprisingly hard to search for this topic on SO (and Google), so I have to ask:
How to prevent propagation / bubbling of the scroll-event ?

Edit:
Working solution thanks to amustill (and Brandon Aaron for the mousewheel-plugin here:
https://github.com/brandonaaron/jquery-mousewheel/raw/master/jquery.mousewheel.js 

$(".ToolPage").bind('mousewheel', function(e, d)  
    var t = $(this);
    if (d > 0 && t.scrollTop() === 0) {
        e.preventDefault();
    }
    else {
        if (d < 0 && (t.scrollTop() == t.get(0).scrollHeight - t.innerHeight())) {
            e.preventDefault();
        }
    }
});

30条回答
深知你不懂我心
2楼-- · 2018-12-31 20:08

I hate necro posting but I was searching for this for MooTools and this was the first that came up. The original MooTools example would work with scrolling up, but not scrolling down so I decided to write this one.

var stopScroll = function (e) {
    var scrollTo = null;
    if (e.event.type === 'mousewheel') {
        scrollTo = (e.event.wheelDelta * -1);
    } else if (e.event.type === 'DOMMouseScroll') {
        scrollTo = 40 * e.event.detail;
    }
    if (scrollTo) {
        e.preventDefault();
        this.scrollTo(0, scrollTo + this.scrollTop);
    }
    return false;
};

Usage:

(function)($){
    window.addEvent('domready', function(){
        $$('.scrollable').addEvents({
             'mousewheel': stopScroll,
             'DOMMouseScroll': stopScroll
        });
    });
})(document.id);
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妖精总统
3楼-- · 2018-12-31 20:09

I am adding this answer for completeness because the accepted answer by @amustill does not correctly solve the problem in Internet Explorer. Please see the comments in my original post for details. In addition, this solution does not require any plugins - only jQuery.

In essence, the code works by handling the mousewheel event. Each such event contains a wheelDelta equal to the number of px which it is going to move the scrollable area to. If this value is >0, then we are scrolling up. If the wheelDelta is <0 then we are scrolling down.

FireFox: FireFox uses DOMMouseScroll as the event, and populates originalEvent.detail, whose +/- is reversed from what is described above. It generally returns intervals of 3, while other browsers return scrolling in intervals of 120 (at least on my machine). To correct, we simply detect it and multiply by -40 to normalize.

@amustill's answer works by canceling the event if the <div>'s scrollable area is already either at the top or the bottom maximum position. However, Internet Explorer disregards the canceled event in situations where the delta is larger than the remaining scrollable space.

In other words, if you have a 200px tall <div> containing 500px of scrollable content, and the current scrollTop is 400, a mousewheel event which tells the browser to scroll 120px further will result in both the <div> and the <body> scrolling, because 400 + 120 > 500.

So - to solve the problem, we have to do something slightly different, as shown below:

The requisite jQuery code is:

$(document).on('DOMMouseScroll mousewheel', '.Scrollable', function(ev) {
    var $this = $(this),
        scrollTop = this.scrollTop,
        scrollHeight = this.scrollHeight,
        height = $this.innerHeight(),
        delta = (ev.type == 'DOMMouseScroll' ?
            ev.originalEvent.detail * -40 :
            ev.originalEvent.wheelDelta),
        up = delta > 0;

    var prevent = function() {
        ev.stopPropagation();
        ev.preventDefault();
        ev.returnValue = false;
        return false;
    }

    if (!up && -delta > scrollHeight - height - scrollTop) {
        // Scrolling down, but this will take us past the bottom.
        $this.scrollTop(scrollHeight);
        return prevent();
    } else if (up && delta > scrollTop) {
        // Scrolling up, but this will take us past the top.
        $this.scrollTop(0);
        return prevent();
    }
});

In essence, this code cancels any scrolling event which would create the unwanted edge condition, then uses jQuery to set the scrollTop of the <div> to either the maximum or minimum value, depending on which direction the mousewheel event was requesting.

Because the event is canceled entirely in either case, it never propagates to the body at all, and therefore solves the issue in IE, as well as all of the other browsers.

I have also put up a working example on jsFiddle.

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刘海飞了
4楼-- · 2018-12-31 20:09

New web dev here. This worked like a charm for me on both IE and Chrome.

static preventScrollPropagation(e: HTMLElement) {
    e.onmousewheel = (ev) => {
        var preventScroll = false;
        var isScrollingDown = ev.wheelDelta < 0;
        if (isScrollingDown) {
            var isAtBottom = e.scrollTop + e.clientHeight == e.scrollHeight;
            if (isAtBottom) {
                preventScroll = true;
            }
        } else {
            var isAtTop = e.scrollTop == 0;
            if (isAtTop) {
                preventScroll = true;
            }
        }
        if (preventScroll) {
            ev.preventDefault();
        }
    }
}

Don't let the number of lines fool you, it is quite simple - just a bit verbose for readability (self documenting code ftw right?)

Also I should mention that the language here is TypeScript, but as always, it is straightforward to convert it to JS.

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只靠听说
5楼-- · 2018-12-31 20:10

Don't use overflow: hidden; on body. It automatically scrolls everything to the top. There's no need for JavaScript either. Make use of overflow: auto;:

HTML Structure

<div class="overlay">
    <div class="overlay-content"></div>
</div>

<div class="background-content">
    lengthy content here
</div>

Styling

.overlay{
    position: fixed;
    top: 0px;
    left: 0px;
    right: 0px;
    bottom: 0px;
    background-color: rgba(0, 0, 0, 0.8);

    .overlay-content {
        height: 100%;
        overflow: scroll;
    }
}

.background-content{
    height: 100%;
    overflow: auto;
}

Play with the demo here.

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萌妹纸的霸气范
6楼-- · 2018-12-31 20:12

This actually works in AngularJS. Tested on Chrome and Firefox.

.directive('stopScroll', function () {
    return {
        restrict: 'A',
        link: function (scope, element, attr) {
            element.bind('mousewheel', function (e) {
                var $this = $(this),
                    scrollTop = this.scrollTop,
                    scrollHeight = this.scrollHeight,
                    height = $this.height(),
                    delta = (e.type == 'DOMMouseScroll' ?
                    e.originalEvent.detail * -40 :
                        e.originalEvent.wheelDelta),
                    up = delta > 0;

                var prevent = function() {
                    e.stopPropagation();
                    e.preventDefault();
                    e.returnValue = false;
                    return false;
                };

                if (!up && -delta > scrollHeight - height - scrollTop) {
                    // Scrolling down, but this will take us past the bottom.
                    $this.scrollTop(scrollHeight);
                    return prevent();
                } else if (up && delta > scrollTop) {
                    // Scrolling up, but this will take us past the top.
                    $this.scrollTop(0);
                    return prevent();
                }
            });
        }
    };
})
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冷夜・残月
7楼-- · 2018-12-31 20:13

jQuery plugin with emulate natural scrolling for Internet Explorer

  $.fn.mousewheelStopPropagation = function(options) {
    options = $.extend({
        // defaults
        wheelstop: null // Function
        }, options);

    // Compatibilities
    var isMsIE = ('Microsoft Internet Explorer' === navigator.appName);
    var docElt = document.documentElement,
        mousewheelEventName = 'mousewheel';
    if('onmousewheel' in docElt) {
        mousewheelEventName = 'mousewheel';
    } else if('onwheel' in docElt) {
        mousewheelEventName = 'wheel';
    } else if('DOMMouseScroll' in docElt) {
        mousewheelEventName = 'DOMMouseScroll';
    }
    if(!mousewheelEventName) { return this; }

    function mousewheelPrevent(event) {
        event.preventDefault();
        event.stopPropagation();
        if('function' === typeof options.wheelstop) {
            options.wheelstop(event);
        }
    }

    return this.each(function() {
        var _this = this,
            $this = $(_this);
        $this.on(mousewheelEventName, function(event) {
            var origiEvent = event.originalEvent;
            var scrollTop = _this.scrollTop,
                scrollMax = _this.scrollHeight - $this.outerHeight(),
                delta = -origiEvent.wheelDelta;
            if(isNaN(delta)) {
                delta = origiEvent.deltaY;
            }
            var scrollUp = delta < 0;
            if((scrollUp && scrollTop <= 0) || (!scrollUp && scrollTop >= scrollMax)) {
                mousewheelPrevent(event);
            } else if(isMsIE) {
                // Fix Internet Explorer and emulate natural scrolling
                var animOpt = { duration:200, easing:'linear' };
                if(scrollUp && -delta > scrollTop) {
                    $this.stop(true).animate({ scrollTop:0 }, animOpt);
                    mousewheelPrevent(event);
                } else if(!scrollUp && delta > scrollMax - scrollTop) {
                    $this.stop(true).animate({ scrollTop:scrollMax }, animOpt);
                    mousewheelPrevent(event);
                }
            }
        });
    });
};

https://github.com/basselin/jquery-mousewheel-stop-propagation/blob/master/mousewheelStopPropagation.js

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