<!DOCTYPE html>
<style>
body {
    margin: 0;
}
.container {
    position: absolute;
    height: 1000px;
    background-color: blue;
}
#child {
    width: 600px;
}
.overflow {
    width: 800px;
    height: 50px;
}
</style>
<div class="container">
    <div id="child">
        <div class="overflow"></div>
    </div>
</div>