scrollable-overlay

A demo of how to prevent body from scrolling when overlay is on, with pure CSS.

Benefit of This Solution

• Pure CSS
• The content page won't skid to top with overlay on
• Works on Mobile Safari

HTML Structure

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

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

Styling

html, body {
    height: 100%;
}
                
.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;
}

Compatibility

Chrome	Safari	Firefox	IE	Mobile Safari
Yes (43.0.2357)	Yes (8.0.6)	Yes (38.0.5)	Partial (!IE8)	Yes (IOS 8.3)

Demo

See it in action here.