JavaScript tests now available on the IE Testing Center

Our commitment to  same markup includes script along with HTML, CSS, SVG, and the other markup that developers use to build the web. To make same markup real, the community needs a set of official tests to assess how interoperable and standards-compliant different browsers are with the latest version of JavaScript, “ECMAScript Fifth Edition” (fondly known as ES5).

As we mentioned in a recent blog post, Ecma International (the standards body behind JavaScript) is working through a process to publish a test suite for ES5. We are contributing tests to this effort, along with other companies.

In the meantime, to make it easier to try out the tests that the standards body is considering, we’re making the ES5 tests we are contributing available on the IE Testing Center.  We’re excited for the official test suite. We’re publishing our submissions to the Ecma test suite now so that the JavaScript and ES5 community can start providing feedback.

We welcome feedback on these tests via Connect. You can log in with any browser and offer comments and suggestions and bugs on the tests. These are some of the same tests that we use as part of our engineering process in developing IE9. 

As Ecma works through getting the official test suite up and running, we will publish additional tests to the IE Testing Center for the community. We will also, of course, submit these tests to the Ecma sponsored ES5 test suite.

Please visit the IE Testing Center and try them out. We look forward to reading your feedback on these tests as we work together to an official ECMAScript test suite for the community.

Alex Chi
Test Manager, JavaScript

Comments (14)

  1. Jim says:

    If you really cared about standards compliance you would support open and royalty free ogg Vorbis for the audio tag. It has better quality than MP3 and none of the patent problems.

  2. Richard says:

    And supporting ogg vorbis would be complying to which standard, exactly?  You can't trot out two unrelated things and imply that not supporting one means not caring about the other.

  3. Josh says:


    Tell that to the developers of Chrome and Safari. WebM uses Vorbis, so I think things will turn out better than you expect.

  4. @Jim:

    HTML5 does NOT say anything beyond that the video/and audio tags exist. So even if every browser company got together and made you have to use some format that they created just for this and that you have to pay them tons of money to use it, they would still be standards compliant.

  5. Neil Dunensach says:

    @Jim – what the hell does OGG Vorbis have to do with java script testing?  I understand what you're saying but you're saying it in the wrong place.

  6. pradeeplive says:

    I have a doubt for a long time on IE.Why does IE not supporting extension platform like firefox,chrome and now safari..?

  7. FremyCompany says:

    Could you file a "fake bug" in connect about your test cases ? Because I don't see which category I should use to report test-suite problems, and what I should answer to some questions like Repros, … (I don't have a bug report yet, but you shoud include it in the post. Posting an IE bug is confusing the first time you do it. Posting a bug for a test-case is even more confusing since the questions are not adapted to this 😉

  8. FremyCompany says:

    Instead of a "fake report", could you instead add this bug to connect and provide a link in this post or in the comments :

    JScript Test 11.13.1-1-1 has a wrong name :


    11.13.1-1-1 simple assignment throws ReferenceError if LeftHandSide is not a reference (string): pass [Source]

    should be 11.13.1-1-1 simple assignment throws ReferenceError if LeftHandSide is not a reference (number): pass [Source]

  9. FremyCompany says:

    Another typo : 11.1.5_4-4-a-2 Object literal – Duplicate data property name ***allowd*** if not in strict mode: pass

  10. hAl says:


    IE supports AAC which is an actual standard unlike Vorbis.

    And modern AAC implementation perform a bit better than vorbis as well.

  11. Tino Zijdel says:

    Even though it is in the non-normative section B of the ES5 spec, alert('abcdefg'.substr(-2)); is still incorrect in IE8. Will this be corrected?

  12. EricLaw [MSFT] says:

    @Tino: In IE5,6,7 and 8 document modes, your test case returns "abcdefg". In IE9 document mode, it returns "fg". This is expected behavior.

    (If you were really asking about changing IE8, the answer is no, that's not the sort of change that would be made for a shipped product).

  13. Tino Zijdel says:

    EricLaw: ofcourse I meant wether it is/will be fixed in IE9. Since I don't run vista or win 7 (yet) I'm not in a position to test it myself. Glad to see confirmation that this is (finally – since this was also already in the non-normative section of ES3)) fixed as well 🙂

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