# Bad value “true” for attribute “hidden” on element “div”.

> Canonical HTML version: https://rocketvalidator.com/html-validation/bad-value-true-for-attribute-hidden-on-element-div
> Attribution: Rocket Validator (https://rocketvalidator.com)
> License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/)

The `hidden` attribute on a `div` (or any HTML element) does not accept `"true"` as a value. It is either a boolean attribute with no value, or it accepts the specific strings `""`, `"hidden"`, or `"until-found"`.

The `hidden` attribute controls whether an element is relevant to the page. When present as a plain boolean attribute (e.g., `<div hidden>`), the browser hides the element entirely and removes it from the accessibility tree. Setting `hidden="true"` is invalid because `"true"` is not one of the allowed states defined in the HTML specification.

The valid states are:

- An empty string (`""`) or the keyword `"hidden"`, both of which map to the "hidden" state. The element is not rendered and is excluded from the accessibility tree.
- The keyword `"until-found"`, which hides the element visually but allows the browser to reveal it if the user searches for content within it (e.g., via Ctrl+F) or navigates to a fragment targeting it.

Since `hidden` is an enumerated attribute with these specific allowed values, `"true"` is treated as an invalid value. Most browsers happen to hide the element anyway when they encounter an unrecognized non-empty value, but the markup is still non-conforming.

## Examples

### Invalid: using `hidden="true"`

```html
<div hidden="true">This content is hidden.</div>
```

### Valid: using the boolean attribute or a valid keyword

```html
<!-- Boolean attribute with no value -->
<div hidden>This content is hidden.</div>

<!-- Explicit "hidden" keyword (equivalent to the above) -->
<div hidden="hidden">This content is hidden.</div>

<!-- Hidden until found by in-page search or fragment navigation -->
<div hidden="until-found">This content is hidden until found.</div>
```