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{{WikiProject banner shell|class=C|
{{WikiProject Computing |importance=Mid |software=y |software-importance=Mid}}
{{WikiProject JavaScript|importance=Top}}
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|author = Miller, F. P., Vandome, A. F., & McBrewster, J.
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|title = JavaScript: JavaScript syntax, client-side JavaScript, JavaScript engine, Ajax (programming), Web interoperability, web accessibility, cross-site scripting, cross-site request forgery, ECMAScript, dynamic HTML
|org = Alphascript Publishing
|comments = {{OCLC|721316846}}, {{ISBN
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* <nowiki>[[Grave accent#Use in programming|backquote]]</nowiki> The anchor (Use in programming) [[Special:Diff/1083439356|has been deleted]]. <!-- {"title":"Use in programming","appear":null,"disappear":{"revid":1083439356,"parentid":1081031463,"timestamp":"2022-04-18T20:37:32Z","removed_section_titles":["As surrogate of apostrophe or (opening) single quote","CITEREFKuhn2001","CITEREF2019","CITEREFEggert2012","Technical notes","ASCII grave","Games","Use in programming","CITEREFOdersky2011"],"added_section_titles":["Unicode"]}} -->
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== Inaccuracy (needs citation) ==
The following statement: "'''else statements must be cuddled (i.e. "} else {" , all on the same line), or else some browsers may not parse them correctly.'''" found in section 5.1 is incorrect. I have been programming in javascript for 4 years, and have never used that programming style. I have yet to notice any browser incompatibilities. If this statement is true, please provide a citation. - [[User:Kickboy|Kickboy]] 04:07, 24 August 2006 (UTC)
:The statement is not present anymore.
:Can we delete this block from 2006? [[Special:Contributions/87.191.37.170|87.191.37.170]] ([[User talk:87.191.37.170|talk]]) 07:26, 9 December 2022 (UTC)
== Inheritance without prototyping, etc. ==
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Should it not be explained that the following:
<
if(x==1){
something()
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somethingelse();
}
</syntaxhighlight>
the else if works like a shorthand if (without {})
<
if(x==1)
do something here
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}
}
</syntaxhighlight>
Sorry if that didn't make sense, I find it hard to explain.
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== For loop: end-condition? ==
<
for (initial;end-condition;loop statement) {
/*
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*/
}
</syntaxhighlight>
The condition should be called ''while-condition'', or just ''condition'', but never ''end-condition''. As in every C-like language, the for{} loop cycles '''while''' the condition is satisfied. --[[User:Comocomocomocomo|Como]] ([[User talk:Comocomocomocomo|talk]]) 14:28, 23 October 2008 (UTC)
No response in several months... I assume everyone agrees, so I dared to change the article. --[[User:Comocomocomocomo|Como]] ([[User talk:Comocomocomocomo|talk]]) 09:26, 3 March 2009 (UTC)
: with no doubt
:<code> for(initial; condition; loopstatement) s; </code>
: is indeed syntactic sugar for
:<code> initial; while(condition){ s; loopstatement; } </code> <!-- Template:Unsigned IP --><small class="autosigned">— Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[Special:Contributions/201.124.237.242|201.124.237.242]] ([[User talk:201.124.237.242#top|talk]]) 09:05, 25 December 2019 (UTC)</small> <!--Autosigned by SineBot-->
== Reworked Methods and Inheritance ==
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The code could be changed to also illustrate the ternary operator <tt>? :</tt> :
<
return diff > 0 ? gcd(segmentB, diff) : gcd(segmentA, -diff)
</syntaxhighlight>
Since the code might be copied, it would be well to change it, after testing, to the more efficient method, in which the second argument to the internal <tt>gcd</tt> is either <tt>A mod B</tt> or <tt>B mod A</tt>, which is approximately equally easy to read; or to the wondrous non-recursive form :
<
function GCD(U, V) { // or HCF
while (true) {
if (!(U %= V)) return V
if (!(V %= U)) return U } }
</syntaxhighlight>
And, for the same reason, the alternative acronym HCF should be included. [[Special:Contributions/82.163.24.100|82.163.24.100]] ([[User talk:82.163.24.100|talk]]) 20:01, 24 July 2009 (UTC)
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<div style="font-size:75%;line-height:150%;margin-left:2.5em;padding-bottom:1.5em;">
<
// Automatic type coercion
//Boolean operands will be converted to a number, if possible, or to a string (if the other is a string)
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alert(true === 1); // false
alert(true === "1"); // false
</syntaxhighlight>
Examples with "falsy" and "truthy" values.
<
alert(true == 3); // false
// 3 is logically true(known as "truthy"), as are all non-0 non-nan numbers. However, it is not "true", even with type coercion.
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alert(false == +'NaN'); // false (shorthand for getting a NaN value)
</syntaxhighlight>
</div>
:I think some of the permutations could potentially be eliminated but it's necessary to show, for example, that neither <code>true==2</code> nor <code>false==2</code> behave the way one might expect.
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== Function example code misleading ==
<
var obj1 = {a : 1};
var obj2 = {b : 2};
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foo(obj1, 3); // Does not affect obj1 at all. 3 is additional parameter
alert(obj1.a + " " + obj2.b); // writes 1 3
</syntaxhighlight>
This is misleading because obj1 can be modified by the function. It is quite odd (in an explanation) to pass a parameter to a function and then ignore it.
Consider:
<
var obj1 = {a : 1};
var obj2 = {b : 2};
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foo(obj1, 3); // Does affect obj1. 3 is additional parameter
alert(obj1.a + " " + obj2.b); // writes 7 3
</syntaxhighlight>
Because the object parameter is passed by reference it can be modified.
This is OR for me. I am just learning. But I was surprised that obj1 can be modified in the function, by p.a=7, yet p=obj2 does not affect obj1. This should be explained. [[User:QuentinUK|QuentinUK]] ([[User talk:QuentinUK|talk]]) 02:27, 28 June 2011 (UTC)
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1) In C whitespace is important for pre-processing.
2
[[User:QuentinUK|QuentinUK]] ([[User talk:QuentinUK|talk]]) 17:20, 21 July 2011 (UTC)
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:As in "how so"? Offhand, semicolon insertion, escaping line terminators in string literals, stray byte order marks... js doesn't normalize Unicode equivalents, strings are just so-many 16-bit unsigned integers.—[[User talk:Machine Elf 1735|<span style="text-shadow:#00FADE 0.05em 0.05em 0.07em;white-space: nowrap;font-family: Fraktur, Mathematica6, Georgia, sans-serif">Machine Elf <sup style="font-size:75%;font-family: Georgia, sans-serif">1735</sup></span>]] 01:22, 24 July 2011 (UTC)
:: It is not unlike C in this respect. So the statement that it is unlike C is incorrect. [[User:QuentinUK|QuentinUK]] ([[User talk:QuentinUK|talk]]) 03:18, 25 July 2011 (UTC)
::: I don't know JavaScript, I saw some code with some lines starting with a semicolon, I wrongly interpreted it as a line comment like the // in C++ because other languages, like several assemblers and Lisp, treat semicolon as a line comment.
:::I learned from this article that JavaScript has an ambiguous syntax with this respect.
:::Syntax ambiguities ''should be a section'' in the article, although I think that the whole article should be rewritten focusing on the syntax of the language.
== Strict equals transitivity ==
The following
<
alert( !0 === Boolean( !0 ) === !!1 === Boolean( 1 ) === true );
alert( !!0 === Boolean( 0 ) === !1 === Boolean( !1 ) === false );
alert( !"" === Boolean( !"" ) === !!"s" === Boolean( "s" ) === true );
alert( !!"" === Boolean( "" ) === !"s" === Boolean( !"s" ) === false );
</syntaxhighlight>
Gives the impression that equality can be chained together. A===B===C being true when they are all equal, this is not the case. [[User:QuentinUK|QuentinUK]] ([[User talk:QuentinUK|talk]]) 10:57, 11 August 2011 (UTC)
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[https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Spread_operator MDN] and [https://msdn.microsoft.com/en-us/library/dn919259(v=vs.94).aspx MSDN] both talk of a spread operator, written "..." and it's not covered here or on other places I've been able to find on Wikipedia about JS or ES6. Then again I've been told that even though major JS sources call ... an [[operator]] it may not technically be an operator. — [[User:Hippietrail|Hippietrail]] ([[User talk:Hippietrail|talk]]) 06:08, 27 January 2016 (UTC)
: I took a try at creating [https://en.wikipedia.org/w/index.php?title=JavaScript_syntax&oldid=741715358#Spread.2Frest_operator a section] about the spread/rest operator "<tt>...</tt>". I placed it in the section on operators, although now that I think about it, it's probably true that it's not an "operator" in the strict sense. It's more like syntactic punctuation, along the same lines as "[]", "{}", commas, and semicolons. In which case, rest parameters should perhaps be moved into the section on functions, and spread syntax should be moved into the section on arrays (and maybe also mentioned in the section on funcions). --[[Special:Contributions/2404:130:0:1000:102E:358C:1F00:94A4|2404:130:0:1000:102E:358C:1F00:94A4]] ([[User talk:2404:130:0:1000:102E:358C:1F00:94A4|talk]]) 06:
== Maintenance and rating of JavaScript articles ==
Concerning editing and maintaining JavaScript-related articles...
=== Collaboration...===
If you are interested in collaborating on JavaScript articles or would like to see where you could help, stop by [[Wikipedia:WikiProject JavaScript]] and feel free to add your name to the participants list. Both editors and programmers are welcome.
=== Where to list JavaScript articles ===
We've found over 300 [[Index of JavaScript-related articles|JavaScript-related articles]] so far. If you come across any others, please add them to that list.
=== User scripts ===
The WikiProject is also taking on the organization of the Wikipedia community's user script support pages. If you are interested in helping to organize information on the user scripts (or are curious about what we are up to), [[Wikipedia talk:WikiProject JavaScript|let us know]]!
If you have need for a user script that does not
yet exist, or you have a cool idea for a user script or gadget, you can post it at [[Wikipedia:User scripts/Requests]]. And if you are a JavaScript programmer, that's a great place to find tasks if you are bored.
=== How to report JavaScript articles in need of attention ===
If you come across a JavaScript article desperately in need of editor attention, and it's beyond your ability to handle, you can add it to our [[Wikipedia:WikiProject JavaScript#JavaScript-related articles that need attention|list of JavaScript-related articles that need attention]].
=== Rating JavaScript articles ===
At the top of the talk page of most every JavaScript-related article is a WikiProject JavaScript template where you can record the quality class and importance of the article. Doing so will help the community track the stage of completion and watch the highest priority articles more closely.
Thank you. [[User talk:The Transhumanist|<i>The Transhumanist</i>]] 01:10, 12 April 2017 (UTC)
== Comments Please ==
I thought the commenting on the examples was very good up until the last example in the Function session & several in the Objects section. Without having the ability to set breakpoints to follow the logic, I had trouble understanding what the author wanted to demonstrate.
I don't know if my sentiment is widespread because I am self-taught and may have missed some implied points along the way. Otherwise, I thought it was well-done. [[User:The Source Whisperer|The Source Whisperer]] ([[User talk:The Source Whisperer|talk]]) 03:58, 6 May 2019 (UTC)
== With statement listed at [[Wikipedia:Redirects for discussion|Redirects for discussion]] ==
[[File:Information.svg|30px|left]]
An editor has asked for a discussion to address the redirect [[With statement]]. Please participate in [[Wikipedia:Redirects for discussion/Log/2019 May 19#With statement|the redirect discussion]] if you wish to do so. <!-- from Template:RFDNote --> — [[User:Arthur Rubin|Arthur Rubin]] [[User talk:Arthur Rubin|(talk)]] 10:56, 19 May 2019 (UTC)
== This '''is not the JavaScript syntax''' is a very long description of the language ==
A programming language syntax is a set of grammar rules which produce any correct written program in the given language. i.e. a program that the compiler/interpreter can analyse (parse) to translate.
It doesn't mean that a grammar produces code with no "bugs", vgr. <code>for(i=m; i<n; 0++)</code> is syntactically correct although evidently meaningless because that program never stops.
A rule restricting <math>m<n</math> and the appropriate increment which will make <code>i<n</code> false to end the loop, ''is semantic, not syntactic''.
Such rules are usually described by means of [[BNF]] grammars or [[syntax diagram]]s.
The article may also include a semantic description of each program construct. (Semi-formal of formal if there is one.)
I don't know JavaScript, but I doesn't seem a monster like [[C++]] with about 300 keywords.
It seems to be a much smaller one, which can be described in a more short article.
'''I agree that this article is too long, but the solution is not to fragment it.''' Instead, should be written, one that meets what the title say '''JavaScript syntax''' or one that includes the semantics and rename it to ''JavaScript syntax and semantics''.
The article should start with the description of the atomic elements like a keyword list, legal variable and other user defined names, the syntax of numbers, and whatever plays the role of words in a sentence. Then the rule that describes a program, followed by each construct of a program. Because I don't know JavaScript, I can't say something more correct. Take it as a general guide for the volunteers that accept this mission.
The source of information can be the standard manual of the language if it exist, please so don't expect hundreds of references.
Just a list of manuals describing the evolution of the language, because some constructs appeared from the first version, others in later versions. It would be ridiculous to tag such article urging for more references. It is a simple task for an experienced JavaScript programmer with some formal education in IT. [[User:Elias|Elias]] ([[User talk:Elias|talk]]) 06:56, 25 December 2019 (UTC)
: {{re|Elias}}. Thumbing up. I agree the article must be shortened. I also suggest to move examples to a separate one.
: {{tq|i=1|[...] The article may also include a semantic description [..] }} It would be disastrous to the article as specs contain a lot (I mean A LOT) of elaborated [[Interface description language|IDL]] definitions for very simple language constructs. I stand for providing simple examples avoiding making article overly academic/specific. <span style="font-size: small" >[[User:Alexander_Davronov|<span style='color:#a8a8a8'>AXO</span><span style="color:#000">NOV</span>]] [[User talk:Alexander_Davronov|(talk)]] [[Special:Contributions/Alexander_Davronov|⚑]]</span> 08:35, 13 October 2020 (UTC)
== Module syntax ==
Module syntax which is the most basic thing of every JS interpreter is missing. I suggest to make section on how module system works per different implementations like browser/server(e.g. Google Chrome/Node.js). I suggest to avoid making it bloated as to address issue pointed out by {{u|Elias}}. <span style="font-size: small" >[[User:Alexander_Davronov|<span style='color:#a8a8a8'>AXO</span><span style="color:#000">NOV</span>]] [[User talk:Alexander_Davronov|(talk)]] [[Special:Contributions/Alexander_Davronov|⚑]]</span> 08:35, 13 October 2020 (UTC)
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