Duplicate ID Attributes

What This Means

Two or more elements in the page share the same id attribute value. The HTML specification requires IDs to be unique within a document.

Why It Matters for SEO

Duplicate IDs cause multiple problems: CSS specificity becomes unpredictable; JavaScript document.getElementById() can only return one element; anchor links (#id fragment URLs) land on an unpredictable element; and accessibility tools (screen readers, browser focus management) behave inconsistently because they rely on unique IDs for aria-labelledby, aria-describedby, and form label associations.

Duplicate IDs frequently arise from CMS templates that repeat component HTML (e.g., a widget with a hardcoded ID rendered multiple times on the same page).

What the Platform Checks

The platform parses the document DOM and groups elements by their id attribute value. Fires when any ID value appears more than once in the document.

How to Fix It

• Find all elements sharing the duplicate ID and make each ID unique.
• In CMS templates that render a component multiple times: use dynamic ID generation (append an index counter or unique identifier to each instance).
• Review component/widget templates that have hardcoded IDs — these must be made dynamic when reused.
• Consider prefixing component IDs with a component name and instance number.