在背景顶部滚动时渐变淡出文本

Question

我一直在寻找一种方法来淡出上下卷轴。我知道在顶部和底部使用2 png的方法，问题是只有在纯色页面上滚动时才显得有用。但我希望它发生在有背景图像的页面上..

有什么想法吗？如果有可能的话？JS，HTML5，CSS？

下面是一张描述效果的图片：

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Answer 1

这可能就是你要找的。

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演示

JSFiddle

HTML

<div class="wrap">
    <p>Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Aenean commodo ligula eget dolor. Aenean massa. Cum sociis natoque penatibus et magnis dis parturient montes, nascetur ridiculus mus. Donec quam felis, ultricies nec, pellentesque eu, pretium quis, sem. Nulla consequat massa quis enim. Donec pede justo, fringilla vel, aliquet nec, vulputate eget, arcu. In enim justo, rhoncus ut, imperdiet a, venenatis vitae, justo. Nullam dictum felis eu pede mollis pretium. Integer tincidunt. Cras dapibus. Vivamus elementum semper nisi. Aenean vulputate eleifend tellus. Aenean leo ligula, porttitor eu, consequat vitae, eleifend ac, enim. Aliquam lorem ante, dapibus in, viverra quis, feugiat a, tellus. Phasellus viverra nulla ut metus varius laoreet. Quisque rutrum. Aenean imperdiet. Etiam ultricies nisi vel augue. Curabitur ullamcorper ultricies nisi. Nam eget dui. Etiam rhoncus. Maecenas tempus, tellus eget condimentum rhoncus, sem quam semper libero, sit amet adipiscing sem neque sed ipsum. Nam quam nunc, blandit vel, luctus pulvinar, hendrerit id, lorem. Maecenas nec odio et ante tincidunt tempus. Donec vitae sapien ut libero venenatis faucibus. Nullam quis ante. Etiam sit amet orci eget eros faucibus tincidunt. Duis leo. Sed fringilla mauris sit amet nibh. Donec sodales sagittis magna.</p>
    <div class="fader"></div>
</div>​

CSS

.wrap {
    position: relative;
    background: url(http://lorempixel.com/output/fashion-q-c-640-480-3.jpg);
    font-family: Helvetica, 'Helvetica Neue', sans-serif;
}

.wrap p {
    color: white;
}

.fader {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(top, rgba(0,0,0,0.7) 0%, rgba(0,0,0,0) 30%, rgba(0,0,0,0) 70%, rgba(0,0,0,0.7) 100%);
    background: -webkit-linear-gradient(top, rgba(0,0,0,0.7) 0%, rgba(0,0,0,0) 30%, rgba(0,0,0,0) 70%, rgba(0,0,0,0.7) 100%);
    background: -moz-linear-gradient(top, rgba(0,0,0,0.7) 0%, rgba(0,0,0,0) 30%, rgba(0,0,0,0) 70%, rgba(0,0,0,0.7) 100%);
    pointer-events: none;
}

编辑:将pointer-events: none添加到CSS以允许正常的文本选择。

Answer 2

下面是我尝试过的方法，看起来很管用：

<html>
<head>
    <title></title>
    <style type="text/css">
        div.bg 
        {
            position: absolute;
            top: 0px;
            left: 0px;
            z-index: 0;
            width: 800px;
            height: 600px;
            background: url([your_background_image]);
        }

        div.txt 
        {
            position: absolute;
            top: 0px;
            left: 50px;
            z-index: 2;
            width: 700px;
            height: 600px;
            font-family: Arial;
            font-size: 30px;
            color: #FFFFFF;
            font-weight: bold;
        }

        div.fader_in
        {
            position: absolute;
            top: 0px;
            left: 0px;
            z-index: 4;
            width: 800px;
            height: 100px;
            filter: progid:DXImageTransform.Microsoft.gradient(startColorstr='#000000', endColorstr='#FFFFFF'); /* for IE */
            background: -webkit-gradient(linear, left top, left bottom, from(#000000), to(#FFFFFF)); /* for webkit browsers */
            background: -moz-linear-gradient(top,  #000000,  #FFFFFF); /* for firefox 3.6+ */ 
            opacity: .5;
            -ms-filter:"progid:DXImageTransform.Microsoft.Alpha(Opacity=50)";
        }

        div.between
        {
            position: absolute;
            top: 100px;
            left: 0px;
            z-index: 4;
            width: 800px;
            height: 400px;
            background: #FFFFFF;
            opacity: .5;
            -ms-filter:"progid:DXImageTransform.Microsoft.Alpha(Opacity=50)";
        }

        div.fader_out
        {
            position: absolute;
            top: 500px;
            left: 0px;
            z-index: 4;
            width: 800px;
            height: 100px;
            filter: progid:DXImageTransform.Microsoft.gradient(startColorstr='#FFFFFF', endColorstr='#000000'); /* for IE */
            background: -webkit-gradient(linear, left top, left bottom, from(#FFFFFF), to(#000000)); /* for webkit browsers */
            background: -moz-linear-gradient(top,  #FFFFFF,  #000000); /* for firefox 3.6+ */ 
            opacity: .5;
            -ms-filter:"progid:DXImageTransform.Microsoft.Alpha(Opacity=50)";
        }
    </style>
</head>
<body>
    <div class="bg">
    </div>
    <div class="txt">Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.
    Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.
    </div>
    <div class="fader_in"></div>
    <div class="between"></div>
    <div class="fader_out"></div>
</body>
</html>

Answer 3

您可以在顶部和底部使用与bg颜色匹配的透明灰色渐变图像：http://www.cssplay.co.uk/menu/fade_scroll.html