Question

On aminutewithbrendan, brendan eich makes an off hand comment implying that serving scripts as

<script type='text/javascript'></script>

is not correct because "text/javascript" is not a valid MIME type and he states "application/javascript" is a valid MIME type.

I only care about serving HTML5 as the doctype.

• Where are the MIME types for <script> defined in the html5 W3C specification ?
• What is browser support like for "text/javascript" and "application/javascript" ?
• Which should be used ? Alternatively should we just not set type at all?

Literal Quote from brendan: (1:48)

… or script type equals application/javascript or application/ecmascript, those are the official MIME types or either one of those made-up ones from HTML4 like text/javascript …

Related:

• script with or without the type
• JavaScript MIME type
• Why set MIME type
• RF4329
• JavaScript MIME type

The union of the related resources doesn’t really answer all three questions.

Answer 1

Where are the MIME types for <script> defined in the html5 W3C specification ?

Nowhere, it has a list (which includes some experimental and deprecated ones) but states that you can use any MIME type you like. MIME types are defined by IANA and text/javascript is officially marked as obsolete in favour of application/javascript

What is browser support like for “text/javascript” and “application/javascript” ?

Not good enough. There are still plenty of browsers around that don’t recognise the latter. (This is, however, only a problem with the type attribute, you can set the HTTP Content-Type header correctly without worrying).

Which should be used ? Alternatively should we just not set type at all?

Since you only care about HTML 5, just omit the type attribute entirely. It is optional and the default language is JavaScript.