[whatwg] HTML 5 Script Tag

Eduard Pascual herenvardo at gmail.com
Thu Aug 6 13:55:49 PDT 2009

On Thu, Aug 6, 2009 at 10:36 PM, Cready, James<jcready at rtcrm.com> wrote:
> Is there any good reason why a <script> tag with the src attribute specified
> can’t be self-closing?
> I understand the need for a <script> tag to have an open and close tag when
> you’re executing javascript inline:
> <script type="text/javascript">
>   alert("Huzzah! I got executed just like you though I would.");
> </script>
> However “best practices” suggest keeping all your scripts external unless
> you absolutely need to use inline scripting. So it seems odd to have an open
> and close tag when you’re including an external JS file since it won’t
> execute anything inside the tags anyway:
> <script src="js/behaviour.js" type="text/javascript">
>   alert("Boo! I won’t get executed just because the src attribute is
> specified. Weak sauce.");
> </script>
> I feel like, if you’re including an external JS file, the syntax should look
> more like the <link> tag used to include CSS files or even the <img> tag
> with it’s src attribute. Both are self-closing and for good reason. Is there
> any possibility of including this syntax in the HTML 5 spec or is there some
> reason this can’t be done?
> <script src="js/behaviour.js" type="text/javascript" />

The <self-closing /> syntax is an XML feature. The trailing slash is
allowed in non-X HTML5 for empty elements only for compatibility with
existing XHTML content served as text/html, but it basically means
nothing. Allowing the slash for elements that are known to be empty is
trivial: it only has to be ignored and things work fine.
The <script> case is a bit more complex: it can have contents, so a
closing </script> is in principle required. While XML offers the
<script ... /> shortcut for code in the form <script ... ></script>,
something like <script src="js/behaviour.js" type="text/javascript" />
would actually be parsed as <script src="js/behaviour.js"
type="text/javascript">, so everything after that will be taken as
part of the script element (and hence won't be shown) until a
</script> is found.

I agree that, for empty elements, self-closing syntax is better than
explicit closing. There could be arguments on self-closing vs.
implicit closing; but in the case of requiring a closing tag for an
empty element, most people would prefer the self-closing syntax. The
main issue here, IMO, is that making this trailing slash relevant
within <script> would make things quite messier for the parser, while
in the general case it just gets ignored. This makes life harder for
implementors and spec writters; and opens the door to some potential
bugs. While I think it's good to put authors above implementors and
spec writters, bugs tend to hurt the user, and the user is above
content authors.

In summary: either use <script /> with XHTML5, or use
<script></script> in (non-X) HTML.

Eduard Pascual

More information about the whatwg mailing list