# Bad value “” for attribute “id” on element X: An ID must not be the empty string. > Canonical HTML version: https://rocketvalidator.com/html-validation/bad-value-for-attribute-id-on-element-x-an-id-must-not-be-the-empty-string > Attribution: Rocket Validator (https://rocketvalidator.com) > License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/) The validator reports “Bad value “” for attribute `id` on element X: An ID must not be the empty string” when any element includes an empty `id` attribute. Per the HTML standard, `id` is a global attribute used as a unique document-wide identifier. An empty identifier is not a valid value and is ignored by some features, leading to hard-to-debug issues. This matters for accessibility and interoperability. Features that depend on IDs—fragment navigation (`#target`), ``, ARIA attributes like `aria-labelledby`/`aria-controls`, and DOM APIs such as `document.getElementById()`—require a non-empty, unique value. Empty IDs break these links, can degrade assistive technology output, and violate conformance, which may hide bugs across browsers. How to fix: - If the element doesn’t need an identifier, remove the `id` attribute entirely. - If it needs one, provide a non-empty, unique value, e.g., `id="main-content"`. - Ensure uniqueness across the page; each `id` must occur only once. - Use simple, predictable tokens: avoid spaces, prefer lowercase letters, digits, hyphens, and underscores (e.g., `feature-1`). While the spec allows a broad range of characters, sticking to URL- and selector-friendly characters avoids pitfalls. ## Examples ### Example that triggers the validator error (empty id) ```html

``` ### Correct: remove an unnecessary empty id ```html

``` ### Correct: provide a meaningful, unique id ```html

``` ### Problematic label association with empty id (invalid) ```html Email ``` ### Correct label–control association ```html Email ``` ### Correct ARIA relationship ```html

Pricing

Choose a plan.

``` ### Correct fragment navigation target ```html

Contact us

``` ### Minimal full document (validated) demonstrating proper ids ```html Valid IDs Example

Welcome

Jump to the details.

Details

```