contain CSS property allows an author to indicate that an element and its contents are, as much as possible, independent of the rest of the document tree. This allows the browser to recalculate layout, style, paint, size, or any combination of them for a limited area of the DOM and not the entire page.
/* Keyword values */ contain: none; contain: strict; contain: content; contain: size; contain: layout; contain: style; contain: paint; /* Global values */ contain: inherit; contain: initial; contain: unset;
This property is useful on pages that contain a lot of widgets that are all independent as it can be used to prevent one widget's CSS rules from changing other things on the page.
|Applies to||all elements|
|Computed value||as specified|
|Canonical order||per grammar|
- Indicates the element renders as normal, with no containment applied.
- Indicates that all containment rules are applied to the element. This is equivalent to
contain: size layout style paint.
- Indicates that all containment rules except size are applied to the element. This is equivalent to
contain: layout style paint.
- Indicates that the element can be sized without the need to examine its dependents for size changes.
- Indicates that nothing outside the element may affect its internal layout and vice versa.
- Indicates that, for properties that can have effects on more than just an element and its descendants, those effects don't escape the containing element.
- Indicates that descendants of the element don't display outside its bounds. If an element is off-screen or otherwise not visible, its descendants are also guaranteed to not be visible.
|CSS Containment Module Level 1||Candidate Recommendation||Initial definition|
|Feature||Android webview||Chrome for Android||Edge mobile||Firefox for Android||Opera Android||iOS Safari||Samsung Internet|
|Basic support||52||52||?||Yes1 2||40||?||?|
1. See bug 1150081 for the overall implementation status.
2. This feature is behind the
layout.css.contain.enabled preference (needs to be set to
true). To change preferences in Firefox, visit about:config.