DevToolBox

CSS Containment Generator

Generate CSS contain property for performance optimization

Selector

Containment Types

Generated CSS

.container {
  contain: layout paint;
}

Current Value

contain: layout paint;

Performance Benefits

  • Layout containment: Prevents internal layout changes from affecting external layout
  • Paint containment: Browser can skip painting elements outside bounds
  • Size containment: Size calculations don't need to traverse children
  • Style containment: CSS counters and quotes are scoped

When to Use

Good Use Cases:

  • Widgets and components
  • Third-party embeds
  • Cards in a grid
  • Independent sections

Avoid When:

  • Content size is unknown
  • Children need to overflow
  • Elements depend on parent layout
  • Browser support is critical