The “language” attribute on the “script” element is obsolete. You can safely omit it.

The language attribute was used in early HTML to specify the scripting language of a <script> block, typically set to values like "JavaScript" or "VBScript". It was deprecated in HTML 4.01 (in favor of the type attribute) and is now fully obsolete in the HTML Living Standard. While browsers still recognize it for backward compatibility, it serves no functional purpose and triggers a validation warning.

The <script> element accepts several standard attributes, but the two most common are type and src. The type attribute specifies the MIME type or module type of the script (e.g., "module" or "application/json"), and src points to an external script file. When writing standard JavaScript, you can omit type entirely because "text/javascript" is the default. The language attribute, however, should always be removed — it is not a valid substitute for type and has no effect in modern browsers.

Why this matters

• Standards compliance: Using obsolete attributes means your HTML does not conform to the current HTML specification. This can cause validation errors that obscure more important issues in your markup.
• Code clarity: The language attribute is misleading to developers who may not realize it’s non-functional. Removing it keeps your code clean and easier to maintain.
• Future-proofing: While browsers currently tolerate the attribute, there is no guarantee they will continue to do so indefinitely. Relying on obsolete features is a maintenance risk.

How to fix it

Simply remove the language attribute from your <script> elements. If you’re using JavaScript (the vast majority of cases), no replacement is needed. If you need to specify a non-default type, use the type attribute instead.

Examples

❌ Obsolete: using the language attribute

<script language="JavaScript">
  console.log("Hello, world!");
</script>

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

✅ Fixed: attribute removed

For inline JavaScript, simply omit the attribute:

<script>
  console.log("Hello, world!");
</script>

For external scripts, only src is needed:

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

✅ Using the type attribute when needed

If you need to specify a script type — for example, an ES module or a data block — use the standard type attribute:

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

<script type="application/json">
  { "key": "value" }
</script>

Note that type="text/javascript" is valid but redundant, since JavaScript is the default. You can safely omit it for standard scripts.

Learn more:

WHATWG Spec

HTML Living Standard: the script element

→

W3C Reference

W3C: HTML5 obsolete features

→