`, `<meta>` tags, `<link>` elements, and `<script>` references. According to the HTML specification, the `<head>` must be the first child element of `<html>` and must appear exactly once. When the browser's parser encounters a second `<head>` tag, or a `<head>` tag after the `<body>` has already opened, it treats it as a "stray" start tag because it violates the expected document structure. This issue commonly arises in several situations: - **Duplicate `<head>` sections** — often caused by copy-paste errors, template includes, or server-side rendering that injects a second `<head>` block. - **`<head>` placed inside `<body>`** — this can happen when restructuring a page or when a component or partial template incorrectly includes its own `<head>`. - **Missing or misplaced closing tags** — if you forget to close the `<head>` with `</head>` or accidentally close `<html>` early, subsequent tags may end up in unexpected positions. This matters because browsers handle stray `<head>` tags inconsistently. Most modern browsers will silently ignore a second `<head>` and attempt to process its children as if they were part of `<body>`, which means your metadata (like `<meta>` charset declarations, stylesheets, or scripts) may not be recognized properly. This can lead to broken styling, encoding issues, missing SEO metadata, and unpredictable behavior across different browsers. ## Examples ### Duplicate `<head>` sections A common mistake is having two `<head>` blocks in the same document: ```html <!DOCTYPE html> <html lang="en"> <head> <title>My Page

# Stray start tag “head”. > Canonical HTML version: https://rocketvalidator.com/html-validation/stray-start-tag-head > Attribution: Rocket Validator (https://rocketvalidator.com) > License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/) The `` element is the container for document metadata — things like the ``, `<meta>` tags, `<link>` elements, and `<script>` references. According to the HTML specification, the `<head>` must be the first child element of `<html>` and must appear exactly once. When the browser's parser encounters a second `<head>` tag, or a `<head>` tag after the `<body>` has already opened, it treats it as a "stray" start tag because it violates the expected document structure. This issue commonly arises in several situations: - **Duplicate `<head>` sections** — often caused by copy-paste errors, template includes, or server-side rendering that injects a second `<head>` block. - **`<head>` placed inside `<body>`** — this can happen when restructuring a page or when a component or partial template incorrectly includes its own `<head>`. - **Missing or misplaced closing tags** — if you forget to close the `<head>` with `</head>` or accidentally close `<html>` early, subsequent tags may end up in unexpected positions. This matters because browsers handle stray `<head>` tags inconsistently. Most modern browsers will silently ignore a second `<head>` and attempt to process its children as if they were part of `<body>`, which means your metadata (like `<meta>` charset declarations, stylesheets, or scripts) may not be recognized properly. This can lead to broken styling, encoding issues, missing SEO metadata, and unpredictable behavior across different browsers. ## Examples ### Duplicate `<head>` sections A common mistake is having two `<head>` blocks in the same document: ```html <!DOCTYPE html> <html lang="en"> <head> <title>My Page

Hello world

``` The second `` triggers the stray start tag error. Merge everything into a single ``: ```html My Page

Hello world

``` ### `` placed inside `` This often happens when a template partial or component includes its own ``: ```html My Page

Hello world

``` Move the metadata into the existing `` section: ```html My Page

Hello world

``` ### `` appearing after `` Sometimes a `` ends up after the closing `` tag, particularly in dynamically assembled pages: ```html My Page

Hello world

``` Again, the fix is to consolidate everything into the single, correctly placed ``: ```html My Page

Hello world

``` ### Tip for template-based systems If you use a templating engine, static site generator, or CMS, check that only your base layout defines the `` element. Partials and components should inject content *into* the existing `` using the templating system's block or slot mechanism, rather than wrapping their metadata in a new `` tag. Search the final rendered HTML output for all occurrences of `