Forwards-compatible syntax proposal

Anne van Kesteren annevk at
Mon May 26 06:52:48 PDT 2008

On Mon, 26 May 2008 15:45:25 +0200, Mike Shaver <mike.shaver at>  
> On Mon, May 26, 2008 at 9:37 AM, Nathan de Vries <nathan at>  
> wrote:
>> i.e. Can a chunk of ES4 defined in a <script type="application/
>> javascript;version=2" /> block interact with ES3 code defined in a
>> <script type="application/javascript" /> block? Has this behaviour
>> been decided on?
> Yes, that's been a major part of the design of the language; toolkits
> need to be able to upgrade to ES4 features without making the
> consumers upgrade wholesale, and vice versa.
> has an example of how ES4 and ES3 code styles interact, and splitting
> the sample program into separate <script> blocks should work just as
> well as it does in with ES3 today.

Yet it does require changes to your deployment because I need to add  
additional <script> elements or change existing ones. It would be better  
if on the HTML side I could just use:

   <script src=library.js>

That already works today, the type attribute default value is  

Given that, something what Ian suggests makes sense I think for the  
transition periods to an improved version of the language.

Anne van Kesteren

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