Wat is CSS Sibling-index en Sibling-count Generator?
sibling-index() and sibling-count() are CSS functions (Chrome 138+) that expose the DOM position of an element among its siblings. sibling-index() returns a 1-based integer representing the element's position. sibling-count() returns the total number of sibling elements. Unlike nth-child selectors that match static patterns, these functions produce dynamic numeric values that you can use in calc() for any property accepting a number or integer. This enables stagger delays, alternating colors, width gradients, and auto-layering without hardcoded selectors.
Snel antwoord
sibling-index() returns the 1-based position of an element among its siblings, and sibling-count() returns the total number of siblings. Use them in calc() to create stagger delays, color cycles, width gradients, and position offsets that adapt automatically as the DOM changes — no nth-child selectors or JavaScript needed.
Beperkingen
- sibling-index() and sibling-count() require Chrome 138+. Firefox and Safari do not yet support these functions as of May 2026.
- The functions return DOM order, not visual order. Elements reordered with CSS flexbox order or grid placement may have an index that does not match their visual position.
- sibling-count() includes all DOM siblings, including those hidden with display: none. Use visibility: hidden to visually hide an element without removing it from the sibling count.
Zo gebruik je deze tool
- Select the property you want to make position-aware, such as animation-delay, background-color, width, opacity, or z-index.
- Choose the sibling function: sibling-index() for per-element positioning or sibling-count() for container-aware scaling.
- Build an expression using calc() to transform the raw index into the desired value range.
- Copy the generated CSS and apply it to the child elements that need position-aware styling.
Waarvoor je het kunt gebruiken
- Create stagger animation delays where each item animates sequentially based on its position among siblings.
- Build a color cycle that rotates through a palette automatically based on element index.
- Generate a width or height gradient across sibling elements without manual nth-child rules.