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@tsaniel
Forked from 140bytes/LICENSE.txt
Created October 5, 2011 10:05
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isWindow

140byt.es

A tweet-sized, fork-to-play, community-curated collection of JavaScript.

How to play

  1. Click the Fork button above to fork this gist.
  2. Modify all the files to according to the rules below.
  3. Save your entry and tweet it up!

Rules

All entries must exist in an index.js file, whose contents are

  1. a valid Javascript function expression, that
  2. optionally self-executes,
  3. contains no more than 140 bytes, and
  4. does not pollute global scope.

All entries must also be licensed under the MIT license.

For more information

The 140byt.es site hasn't launched yet, but for now follow @140bytes on Twitter.

140byt.es is brought to you by Jed Schmidt. It was inspired by work from Thomas Fuchs and Dustin Diaz.

function(){
/* Rules:
(1) anonymous function // make sure
(2) may be self-executing // to annotate
(3) <=140 bytes // your code
(4) no globals // so everyone
(5) MIT license // can learn
(6) have a good time! // from it!
*/}
function(){/*Rules: (1) anonymous function (2) may be self-executing (3) <=140 bytes (4) no globals (5) MIT license (6) have a good time!*/}
Copyright (c) 2011 YOUR_NAME_HERE, YOUR_URL_HERE
Permission is hereby granted, free of charge, to any person obtaining
a copy of this software and associated documentation files (the
"Software"), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished to do so, subject to
the following conditions:
The above copyright notice and this permission notice shall be
included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
{
// [REQUIRED] A name for your library.
// This must match /^[a-z_]\w*$/i
"name": "140bytes",
// [OPTIONAL] A description of your library, phrased as a verb predicate.
// The gist description is used by default.
"description": "Explain the 140byt.es rules."
// [OPTIONAL] Up to 5 keywords used for indexing.
"keywords": [
"140bytes",
"master",
"rules"
]
}
@nikola
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nikola commented Oct 5, 2011

I'd say it's safe to eliminate the Object {} scope from the toString() call.

@atk
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atk commented Oct 6, 2011

You can even eliminate the toString call completely, because .test() coerces its first argument into String.

@tsaniel
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tsaniel commented Oct 7, 2011

Thanks for your ideas, @nikola and @atk!
However,
@nikola: This may lead to error in older IE versions.
@atk: Something like 'w]' will pass the test.

@atk
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atk commented Oct 7, 2011

You could try a&&a.alert additionally

@tsaniel
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tsaniel commented Oct 7, 2011

@atk: Thanks again! But an fake object {alert:1,toString:function(){return 'w]'}} still passes the test.

@atk
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atk commented Oct 7, 2011

That's true. How about (a||0).constructor===this.Window? Works in all modern browsers (not in IE 7 or older).

@nikola
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nikola commented Oct 7, 2011

Not in Chrome 14.

this.constructor !== window

@atk
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atk commented Oct 7, 2011

Damn, there it's DOMWindow... /Wi/.test(a.constructor), maybe?

@tsaniel
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tsaniel commented Oct 7, 2011

{constructor:'Wi'}

@atk
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atk commented Oct 9, 2011

Let's try this:

function(a,b){b=this.Window||this.DOMWindow;return!!a&&b?a instanceof b:a==(b=a.document)&&b!=a}

@tsaniel
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tsaniel commented Oct 10, 2011

It is sad that it won't work with iframes...

@atk
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atk commented Oct 10, 2011

Rewritten to probably work with (i)frames:

function(a,b){return!!a&&(b=a.Window||a.DOMWindow)?a instanceof b:a==(b=a.document)&&b!=a}

@tsaniel
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tsaniel commented Oct 10, 2011

It cannot work with my chromium 12...

@atk
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atk commented Oct 10, 2011

Alas, it's not exposed in Chrome. OK, let's try this:

function(a,b){return!!a&&(b=top.constructor)?a instanceof b:a==(b=a.document)&&b!=a}

@tsaniel
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tsaniel commented Oct 11, 2011

It won't work with (i)frame as well, because the scope of top differs from (i)frame.

@atk
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atk commented Oct 11, 2011

Right. Any idea how to get DOMWindow in Chrome if its not exposed?

@tsaniel
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tsaniel commented Oct 11, 2011

The magic __proto__?

@atk
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atk commented Oct 11, 2011

Doesn't help very much, because it is different between frames.

@tsaniel
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tsaniel commented Oct 11, 2011

I think it is hard. In fact, the original code is enough.

@phoetry
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phoetry commented Dec 2, 2011

Try this:

function(a,b){return a&&a==a[b='window']&&a==a[b][b]}

@nikola
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nikola commented Dec 2, 2011

Clever. Exploiting the fact that any global object is exposed as a property of window, and window itself is a global object.

@tsaniel
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tsaniel commented Dec 3, 2011

@phoetry: It's clever but it won't work.

var a = {};
a.window = a;
(function(a,b){return a&&a==a[b='window']&&a==a[b][b]})(a) // true

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