Subj : Re: JavaScript - Strict Mode?
To   : Brendan Eich <brendan@meer.net>
From : Phil Schwartau <pschwartau@netscape.com>
Date : Wed Apr 02 2003 02:28 pm

> This worked when I implemented it the other year; I hope it still does.

I checked; it does still work. It should be put into its own <script> block:

<script>
_options.strict = true;
</script>

<script>
function f() {1;}
</script>

This produces the expected strict warning in the JS Console:

---------> Warning: useless expression

And setting |werror| turns it into a hard error:

<script>
_options.strict = true;
_options.werror = true;
</script>

<script>
function f() {1;}
</script>

---------> Error: useless expression


However, if it's all done in one <script> block, no error shows up:

<script>
_options.strict = true;
_options.werror = true;
function f() {1;}
</script>


That's the way it has to be, since inside a JS compilation unit, a function statement gets compiled before property assignments. Different <script> blocks are separate JS compilation units, and allow us to guarantee that the strict options get set first.

Just an FYI to users -
Phil



Brendan Eich wrote:
> Phil Schwartau wrote:
> 
>> A strict mode already exists. In the Mozilla browser, do this:
>>
>>  Edit > Preferences > Debug > check "Show strict JavaScript warnings"
>>
>> Then adjust
>>  Tools > Web Development > JavaScript Console
>> to make sure you see warnings as well as errors. (In the menubar under 
>> the File menubar, select "All"). 
> 
> 
> 
> Also, script for a page can set this option by setting
> 
> _options.strict = true;
> 
> This worked when I implemented it the other year; I hope it still does.  
> There's also an _options.werror property you can set to turn warnings 
> into errors.
> 
> /be
>

.