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Sheath rule

best-practices-no-script-style-type

Omit unnecessary type attribute on <script> and <style> elements.
Package
Core
Category
Best Practices
Default severity
info by default
Auto-fix
Auto-fix available

#Why

In HTML5, the default type for <script> is text/javascript and for <style> is text/css. Specifying these default values is unnecessary and adds to page weight.

#Examples

#Bad

<!-- Unnecessary type on script -->

<script type="text/javascript">

    console.log('Hello');

</script>

<script type="application/javascript" src="app.js"></script>



<!-- Unnecessary type on style -->

<style type="text/css">

    body { margin: 0; }

</style>

#Good

<!-- No type needed for JavaScript -->

<script>

    console.log('Hello');

</script>

<script src="app.js"></script>



<!-- No type needed for CSS -->

<style>

    body { margin: 0; }

</style>



<!-- Keep type="module" - it's required! -->

<script type="module" src="app.mjs"></script>



<!-- Keep non-default types -->

<script type="application/ld+json">

    { "@context": "https://schema.org" }

</script>

#Auto-fix

The fixer removes unnecessary type attributes:

<!-- Before -->

<script type="text/javascript" src="app.js"></script>



<!-- After -->

<script src="app.js"></script>

#Important: Keep type="module"

The type="module" attribute is required for JavaScript modules and is not removed. The following values are reported:

  • Any standard JavaScript MIME essence on <script>, including legacy values such as text/javascript1.5 and application/x-javascript
  • Leading and trailing HTML ASCII whitespace is ignored when classifying a script type, matching browser script processing
  • Empty and whitespace-only type attributes on <script> are unnecessary too
  • type="text/css" on <style>

An empty type on <style> is preserved. Unlike omission or text/css, it does not declare CSS, so removing it could make previously inert content apply.

Script type matching is ASCII case-insensitive but exact. A value with surrounding spaces or MIME parameters is a data-block type in HTML and is not removed.

#References

#Related Rules