JScript vs. JavaScript differences

Discussion in 'Javascript' started by VK, Apr 25, 2010.

  1. VK

    VK Guest

    I propose to collect all known differences between JScript vs.
    JavaScript engines. I am using neutral word "difference" because the I
    don't want to transform it into yet another discussion about the
    eternal of "one who's name should not be spelled" etc. Simply: they do
    like that, X does like that, be warned.

    It also only and exclusively about pure Javascript engine, so even
    window.alert, confirm, prompt are out for now. Only the engine, Global
    and down.

    My initial contribution:

    Two "God's Bugs", because subjects of special hate and obsession of
    Brendan Eich himself:

    GB1) Named FunctionExpression treatment

    GB2) Terminal elision treatment. That one I remind is that
    var arr = [0,1,]
    window.alert(arr.length);
    // al. == 2
    // IE == 3

    1) Pending comma in object initializer.
    var foo = {
    'a':1,
    'b':2,
    }
    // al. OK
    // IE gives syntax error
    Maybe a distant relative of GB2 above. Can be very nasty without a
    possibility of parallel testing on IE as occasional typo will not be
    noticed, so be warned.

    Anyone else? ;-)
    VK, Apr 25, 2010
    #1
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  2. VK

    VK Guest

    On Apr 26, 2:37 am, Stefan Weiss <> wrote:
    > On 26/04/10 00:17, VK wrote:
    >
    > > I propose to collect all known differences between JScript vs.
    > > JavaScript engines.

    >
    > Between JScript and JavaScript or between JScript and ECMAScript? In
    > this context, the word "JavaScript" really is ambiguous; it appears to
    > refer exclusively to Netscape/Mozilla's implementation.


    For me there is only JavaScript. I don't know what "ECMAScript" and
    don't want to know. Yet to not transform it into a fruitless rwar
    discussion, let say JScript vs. all other prominent implementations.
    If "prominent implementations" absolutely necessarily requires a
    separate fruitless rwar discussion, let's say like this:

    "Microsoft JScript and Mozilla Firefox ECMA-262 3rd. ed. part
    implementations: differences between them"

    Any political correctness objections to that?


    > You could start with this document: "[MS-ES3EX]: Microsoft JScript
    > Extensions to the ECMAScript Language Specification Third Edition"http://msdn.microsoft.com/en-us/library/ff521046(VS.85).aspx


    Who the hey cares about *extensions"? And who out of average coders
    will study this documents in hope to see something useful for future
    use? Let's make a small thing that no one did yet: get together all
    implementation differences within the grammar defined in ECMA-262
    3rd.ed.
    Then sort out i) important to know and ii) important for profound
    theoretical discussions only. Say GB2 is of the 2nd kind IMHO. When
    the last time anyone used elision and how many average coders even
    know about it?
    From the other side - again IMHO - pending comma difference is
    important to know. Who ever coded manually knows how often one types
    extra comma automatically when filling the initializer.
    VK, Apr 25, 2010
    #2
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  3. VK

    VK Guest

    On Apr 26, 3:19 am, Stefan Weiss <> wrote:
    > Why did you ask for comments if you don't want to hear the answers?


    Sorry if being too aggressive but I am really frustrated with the
    group situation where many people are ready to talk about everything
    except the applied programming. There is no JavaScript, there are no
    prominent browsers, there is not this, there is not that, any code may
    fail on this or that browser with 0.0000000000001% market share, DOM 0
    is non-standard extension that can be missed (sic!), XHR is not
    standard so better not used it (sic!), let's better talk about some
    fresh W3C paper...

    Microsoft JScript - Mozilla JavaScript, only parts implemented by
    requirements of ECMA-262 3rd.ed.
    It is not all - but 70%-90% coverage at once is good enough for a
    starter.

    P.S. In the linked MS document I searched for "elision" - zero
    matches. So whatever it is, it is already lesser full than my initial
    post.

    Again: I want to get together cases that people should be really aware
    while making their code. Something one once encountered and couldn't
    get what's wrong right away. Of course c.l.j. gurus never were in such
    situations, whatever they do and see is crystal clear to them by
    definition. Well, I am not so perfect as they are and such situations
    did and do occur with me. Maybe - just maybe - I am not alone of the
    kind. In this case some more contributions to this thread may follow.
    VK, Apr 26, 2010
    #3
  4. VK wrote:

    > I propose to collect all known differences between JScript vs.
    > JavaScript engines.
    > [...]
    > Anyone else? ;-)


    Good morning, sunshine!

    <http://PointedEars.de/es-matrix>


    PointedEars
    --
    realism: HTML 4.01 Strict
    evangelism: XHTML 1.0 Strict
    madness: XHTML 1.1 as application/xhtml+xml
    -- Bjoern Hoehrmann
    Thomas 'PointedEars' Lahn, Apr 26, 2010
    #4
  5. VK wrote:

    > I propose to collect all known differences between JScript vs.
    > JavaScript engines.
    > [...]
    > Anyone else? ;-)


    This wheel has already been invented; you are welcome to improve it:

    <http://PointedEars.de/es-matrix>


    PointedEars
    --
    realism: HTML 4.01 Strict
    evangelism: XHTML 1.0 Strict
    madness: XHTML 1.1 as application/xhtml+xml
    -- Bjoern Hoehrmann
    Thomas 'PointedEars' Lahn, Apr 26, 2010
    #5
  6. In comp.lang.javascript message <2f7f2bb0-0b3a-4a52-9b6f-ba3bc2fca523@x3
    g2000yqd.googlegroups.com>, Sun, 25 Apr 2010 15:17:34, VK
    <> posted:
    >I propose to collect all known differences between JScript vs.
    >JavaScript engines. I am using neutral word "difference" because the I
    >don't want to transform it into yet another discussion about the
    >eternal of "one who's name should not be spelled" etc. Simply: they do
    >like that, X does like that, be warned.


    Look at the big table in my js-datex.htm, noting that the yellow column
    is computed by your browser. It does not (yet?) include the one in my
    js-maths.htm#frSt. Include default date-to-string.

    Opera 10.50 & 10.51 differ from ECMA, other browsers, and sanity in
    handling of offsets from GMT. You will need to consider whether to deal
    with "JavaScript" bugs (note also the handling of the month "Octopus").

    You will be able to classify some differences as evident bugs, and
    others as differing interpretations of what is not, or is badly,
    specified.

    --
    (c) John Stockton, nr London, UK. ?@merlyn.demon.co.uk Turnpike v6.05 MIME.
    Web <URL:http://www.merlyn.demon.co.uk/> - FAQqish topics, acronyms & links;
    Astro stuff via astron-1.htm, gravity0.htm ; quotings.htm, pascal.htm, etc.
    No Encoding. Quotes before replies. Snip well. Write clearly. Don't Mail News.
    Dr J R Stockton, Apr 26, 2010
    #6
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