svelte:head for document head

Introduction

The svelte:head tag lets you add or change content inside the HTML document's <head> section from your Svelte component. This helps set page titles, meta tags, and links dynamically.

You want to set a custom page title for each page in your app.

You need to add meta tags for SEO or social sharing dynamically.

You want to include external stylesheets or fonts in the document head.

You want to add a favicon or other link tags based on component state.

Syntax

Svelte

<svelte:head>
  <!-- head content here -->
</svelte:head>

Anything inside svelte:head will be placed inside the HTML <head> tag.

You can use expressions and reactive variables inside svelte:head just like in the main component.

Examples

Sets a static page title in the document head.

Svelte

<svelte:head>
  <title>My Page Title</title>
</svelte:head>

Uses a variable to set the page title dynamically.

Svelte

<script>
  let pageTitle = 'Welcome';
</script>

<svelte:head>
  <title>{pageTitle}</title>
</svelte:head>

Adds meta description and favicon link tags to the head.

Svelte

<svelte:head>
  <meta name="description" content="This is a Svelte app">
  <link rel="icon" href="/favicon.ico">
</svelte:head>

Sample Program

This Svelte component sets the page title and viewport meta tag inside the document head. The main content shows a heading using the same title variable.

Svelte

<script>
  let title = 'Home Page';
</script>

<svelte:head>
  <title>{title}</title>
  <meta name="viewport" content="width=device-width, initial-scale=1">
</svelte:head>

<main>
  <h1>Welcome to the {title}</h1>
</main>

Important Notes

Only one svelte:head block is needed per component, but you can have multiple if you want.

When components unmount, their head tags are removed automatically if they were added dynamically.

Use svelte:head to improve SEO and user experience by controlling the document head from your components.

Summary

svelte:head lets you add tags inside the HTML <head> from Svelte components.

You can set titles, meta tags, links, and more dynamically using variables.

This helps make your app's pages more meaningful and SEO-friendly.

Practice

1. What is the main purpose of the <svelte:head> tag in a Svelte component?

easy

A. To add or modify elements inside the HTML <head> section of the page.

B. To create a new HTML section inside the body of the page.

C. To style the component using CSS.

D. To handle user input events in the component.

Solution

1. Step 1: Understand the role of <svelte:head>

   The <svelte:head> tag is specifically designed to insert or update tags inside the HTML <head> section, such as titles and meta tags.

2. Step 2: Compare with other options

   Options A, B, and C describe unrelated tasks: event handling, body content, and styling, which are not the purpose of <svelte:head>.

3. Final Answer:

   To add or modify elements inside the HTML <head> section of the page. -> Option A

4. Quick Check:

   svelte:head modifies <head> = D [OK]

Hint: Remember: svelte:head changes the document head, not body content. [OK]

Common Mistakes:

• Confusing svelte:head with component body content
• Thinking it styles components directly
• Assuming it handles events

2. Which of the following is the correct syntax to set the page title using <svelte:head> in a Svelte component?

easy

A. My Page

B. My Page

C. My Page

D. My Page

Solution

1. Step 1: Identify correct tag usage

   The correct tag to modify the document head in Svelte is <svelte:head>, not <svelte-head> or <head> inside it.

2. Step 2: Check nesting rules

   You place the <title> tag directly inside <svelte:head>, without nesting another <head> tag inside it.

3. Final Answer:

   <svelte:head><title>My Page</title></svelte:head> -> Option C

4. Quick Check:

   Correct svelte:head syntax = C [OK]

Hint: Use exactly with direct children tags inside. [OK]

Common Mistakes:

• Using <head> instead of
• Adding extra <head> inside
• Misspelling the tag as

3. Given this Svelte component code, what will be the page title after rendering?

<script>
  let pageTitle = 'Welcome';
</script>

<svelte:head>
  <title>{pageTitle} to Svelte</title>
</svelte:head>

<h1>Hello!</h1>

medium

A. {pageTitle} to Svelte

B. Welcome to Svelte

C. pageTitle to Svelte

D. Hello!

Solution

1. Step 1: Understand variable interpolation in svelte:head

   The variable pageTitle is set to 'Welcome' and used inside the <title> tag with curly braces, so it will be replaced by its value.

2. Step 2: Determine the final title text

   The title becomes 'Welcome to Svelte' because the variable is replaced and concatenated with the string ' to Svelte'.

3. Final Answer:

   Welcome to Svelte -> Option B

4. Quick Check:

   Variable interpolation works in svelte:head = B [OK]

Hint: Variables inside { } in svelte:head render their values. [OK]

Common Mistakes:

• Thinking variables show as literal text
• Confusing page content with title text
• Ignoring interpolation syntax

4. What is wrong with this Svelte code snippet?

<svelte:head>
  <title>My Site</title>
  <meta name="description" content="A cool site">
</svelte:head>

medium

A. Nothing is wrong; this code is valid.

B. The <title> tag cannot be used inside <svelte:head>.

C. The <meta> tag must be self-closed with /> in Svelte.

D. The <meta> tag is missing a closing slash.

Solution

1. Step 1: Check HTML validity inside svelte:head

   In HTML5, the <meta> tag is a void element and does not require a closing slash. It is valid to write it without />.

2. Step 2: Confirm usage of title and meta tags

   Both <title> and <meta> tags are allowed inside <svelte:head> to modify the document head.

3. Final Answer:

   Nothing is wrong; this code is valid. -> Option A

4. Quick Check:

   HTML5 void tags don't need closing slash = A [OK]

Hint: Void tags like <meta> don't need closing slash in HTML5. [OK]

Common Mistakes:

• Adding unnecessary closing slash to <meta>
• Thinking <title> is disallowed in svelte:head
• Confusing XHTML rules with HTML5

5. You want to dynamically update the page description meta tag based on a component variable desc. Which Svelte code correctly updates the meta description in the document head when desc changes?

<script>
  let desc = 'Initial description';
</script>

<!-- Choose the correct svelte:head usage -->

hard

A.

B.

C.
{desc}

D.

Solution

1. Step 1: Understand attribute binding in svelte:head

   To dynamically set an attribute value, use curly braces without quotes around the variable, like content={desc}.

2. Step 2: Check invalid options

   uses quotes around {desc}, so it treats it as a literal string, not variable. {desc} incorrectly places content inside <meta>, which is a void tag and cannot have children. misses curly braces around desc.

3. Final Answer:

   <svelte:head> <meta name="description" content={desc}> </svelte:head> -> Option D

4. Quick Check:

   Use content={variable} without quotes for dynamic meta tags = A [OK]

Hint: Use content={desc} without quotes for dynamic meta tag content. [OK]

Common Mistakes:

• Putting quotes around {desc} making it a string
• Adding children inside <meta> tag
• Using incorrect tag closing for void elements