SiteLint documentation and guidelines

Position sticky

Description

The position: sticky CSS property allows an element to switch between relative and fixed positioning, depending on the user’s scroll position. A sticky element toggles between relative and fixed based on the scroll position, making it stick to a specified position within its parent container as the user scrolls. Proper use of position: sticky can enhance navigation and accessibility by keeping important content in view.

Disabilities impacted

  • Visual impairments: users with visual impairments may benefit from sticky elements, such as navigation menus, staying in view, reducing the need for excessive scrolling, and aiding orientation.
  • Motor impairments: users with motor impairments who find scrolling challenging can benefit from sticky elements that keep navigation or important actions readily accessible.
  • Cognitive disabilities: users with cognitive disabilities can find sticky elements helpful as they provide constant access to key navigation or interactive components, reducing cognitive load.

Why it matters

Using position: sticky appropriately ensures that important elements, like navigation bars or action buttons, remain accessible and visible, improving the overall user experience. It helps users maintain context and access critical controls without needing to scroll back to the top of the page. This enhances usability, particularly for users with disabilities.

Coding problems and solutions

Common coding problems

  • Unsupported or incompatible browsers: some old browser may not support position: sticky;.
  • Incorrect container overflow: sticky positioning may fail if any ancestor element has overflow: hidden, overflow: scroll, or overflow: auto.
  • Unexpected behavior with margins: sticky elements might behave unexpectedly if margins are not handled correctly.
  • Insufficient height or width: elements with position: sticky; require explicit height and width definitions to function correctly.

How to Fix It

Unsupported or incompatible browsers

Ensure that the target browsers support position: sticky and provide fallbacks if necessary.

Correct example
.sticky {
  @supports (position: sticky) {
    position: sticky;
    top: 0;
  }
}

Manage container overflow

Ensure that no ancestor element of the sticky element has an overflow property that could interfere with sticky positioning.

Correct example
.container {
    overflow: visible; /* Ensure proper sticky behavior */
}
.sticky {
    position: sticky;
    top: 0;
}

Handle margins appropriately

Be aware of how margins affect sticky positioning and test thoroughly.

Correct example
.sticky {
    position: sticky;
    top: 10px; /* Adjust as needed */
    margin-top: 20px; /* Be mindful of margins */
}

Known limitations

  • Browser compatibility: ensure that all target browsers support position: sticky. Use feature detection like @supports in CSS and provide fallbacks where necessary.
  • Performance considerations: excessive use of sticky positioning on many elements can impact performance, especially on complex pages.
  • Complex layouts: in complex layouts, ensure that sticky elements do not overlap or interfere with other content, maintaining a clear and accessible interface.

Resources