---
title: a11y/deprecated-attr · Deprecated HTML attribute
description: An attribute the HTML spec data marks deprecated on this element has its behavior defined by legacy compatibility, not by the standard.
---

**Severity:** info · **Category:** a11y

Scored `info` rather than `warning`: the attribute may still work today. The finding is that the standard no longer defines what it means, and a CSS or modern-attribute replacement exists.

## What it checks

Flags an attribute the HTML spec data marks deprecated (or obsolete) **on that element**, such as `iframe[frameborder]`, `td[width]`, `body[bgcolor]`, `hr[size]` and `style[type]`, in component source.

Deprecation is per element: `width` is deprecated on `<td>` and current on `<img>`, so only the first is reported. An element with several deprecated attributes yields **one** finding listing them, anchored at the start tag, so one `disable-next-line` directive above the element silences it, however many lines the tag spans.

Not flagged:

- A deprecated attribute on an element `a11y/deprecated-element` reports (`<font color>`, `<marquee behavior>`): one finding per element. That holds even when `a11y/deprecated-element` is off or suppressed inline: this rule skips obsolete elements by name.
- Anything inside `<svg>`, or in a component declaring `<svelte:options namespace="svg" />`; content under `<foreignObject>` returns to HTML.
- The global attribute groups (`xml:lang`, `xlink:href`, `onwebkit*`). Only an element's own attribute table is consulted, so `<use xlink:href="#icon">` in an SVG sprite is never reported.
- Attributes only marked `nonStandard` or `experimental`. One marked both `deprecated` and `nonStandard` (`hr[size]`) is reported.
- A component's own `<style>` block: it is the component stylesheet, not an element. A `<style type="text/css">` inside `<svelte:head>` is an element and is reported.

```svelte
<iframe src="/embed" frameborder="0" title="Map"></iframe>
<td width="120">…</td>
```

**Coverage follows the dataset**, which is the `deprecated`/`obsolete` columns of the vendored HTML spec data (`@markuplint/html-spec`) and tracks MDN's status rather than the WHATWG obsolete-features list. That cuts both ways: an attribute MDN marks deprecated is reported even where the standard's word differs (`a[attributionsrc]`), and WHATWG-obsolete attributes MDN never documented, among them `p[align]`, `td[nowrap]` and `html[manifest]`, are not reported.

## Why it matters

A deprecated attribute's behavior is defined by what browsers still do for legacy pages, not by the standard, and each has a replacement whose behavior is defined, usually CSS and sometimes a modern attribute.

## How to fix

Move the presentation to CSS, or use the attribute the deprecated one was superseded by:

```svelte
<iframe src="/embed" title="Map" style="border: 0"></iframe>
<td style="width: 120px">…</td>
```

## Mode differences

None. This rule reads source, the same `.svelte` and `.ts` files, everywhere it runs. The CLI, the Vite plugin's build pass, and the live dashboard's static baseline all report it identically, and the rendered-HTML pass never re-evaluates it. Scoping a run with `--route` skips it: component-scoped rules have no route to attribute a finding to.

## Disabling

Silence a single element with `<!-- svelte-vitals-disable-next-line a11y/deprecated-attr -->`, or turn the rule off:

```js svelte-vitals.config.js
export default {
  rules: {
    'a11y/deprecated-attr': 'off'
  }
};
```