/* Keyword values */
overscroll-behavior-x: auto; /* default */
overscroll-behavior-x: contain;
overscroll-behavior-x: none;

/* Global values */
overscroll-behavior-x: inherit;
overscroll-behavior-x: initial;
overscroll-behavior-x: revert;
overscroll-behavior-x: revert-layer;
overscroll-behavior-x: unset;

The overscroll-behavior-x property is specified as a keyword chosen from the list of values below.

auto

The default scroll overflow behavior occurs as normal.

contain

Default scroll overflow behavior (e.g., "bounce" effects) is observed inside the element where this value is set. However, no scroll chaining occurs on neighboring scrolling areas; the underlying elements will not scroll. The contain value disables native browser navigation, including the vertical pull-to-refresh gesture and horizontal swipe navigation.

none

No scroll chaining occurs to neighboring scrolling areas, and default scroll overflow behavior is prevented.

overscroll-behavior-x = 
  contain  |
  none     |
  auto     

In our simple overscroll-behavior-x example (see source code also), we have two block-level boxes, one inside the other. The outer box has a large width set on it so the page will scroll horizontally. The inner box has a small width (and height) set on it so it sits comfortably inside the viewport, but its content is given a large width so it will scroll horizontally.

By default, when the inner box is scrolled and a scroll boundary is reached, the whole page will begin to scroll, which is probably not what we want. To avoid this, you can set overscroll-behavior-x: contain on the inner box:

main > div {
  height: 300px;
  width: 500px;
  overflow: auto;
  position: relative;
  top: 100px;
  left: 100px;
  overscroll-behavior-x: contain;
}

• Take control of your scroll: customizing pull-to-refresh and overflow effects
• The mapped logical properties: overscroll-behavior-inline, overscroll-behavior-block