Because, at least in HTML 4.01 and XHTML 1(.1), the type
attribute for <script>
elements is required.
In HTML 5, type
is no longer required.
In fact, while you should use text/javascript
in your HTML source, many servers will send the file with Content-type: application/javascript
. Read more about these MIME types in RFC 4329.
Notice the difference between RFC 4329, that marked text/javascript
as obsolete and recommending the use of application/javascript
, and the reality in which some browsers freak out on <script>
elements containing type="application/javascript"
(in HTML source, not the HTTP Content-type header of the file that gets send). Recently, there was a discussion on the WHATWG mailing list about this discrepancy (HTML 5's type
defaults to text/javascript
), read these messages with subject Will you consider about RFC 4329?