Where are constructors such as, `new Image()` and `new Option()`, documented?

Question

Not at Mozilla but:

• for image:
  Thanks to Rickard for identifying
  http://www.w3.org/html/wg/drafts/html/CR/embedded-content-0.html#dom-image
  that provides the DOM interface constructor details.
• for option:
  http://www.w3.org/html/wg/drafts/html/CR/forms.html#dom-option
  also gives the DOM interface constructor details.
  (Found using:
  http://www.google.com/search?client=ubuntu&channel=fs&q=constructor+site%3Adev.w3.org%2Fhtml5&ie=utf-8&oe=utf-8)

Given these references, it is moot whether mozilla.org, as asked below, documents the same.

---

Specifically, where at mozilla.org are constructors like new Image() and new Option() documented in a contemporary context?

Archaic documentation,

• Image() defined at http://devedge-temp.mozilla.org/library/manuals/2000/javascript/1.3/reference/image.html
• Option() defined at http://devedge-temp.mozilla.org/library/manuals/2000/javascript/1.3/reference/option.html

describes the existence of these constructors implicating them as intrinsic JavaScript language components, which is incorrect.

javascript: alert([new Image(), '\n\n', new  Option()]) 

clearly indicates their manifest existence by displaying

[object HTMLImageElement],

,[object HTMLOptionElement]

Rhetorically, what about:

javascript:alert([new Anchor(), new Preserve(), new Form(),,, ]) 

What other primitive elemental DOM constructors are there? Or, are there no more?

Is it anathema to, and inconsistent with the DOM paradigm used by Mozilla, to incorporate the programming definitions of new Image() and new Option() etc., explaining their absence? Yet, these constructors are clearly not intrinsic to the language specification of JavaScript and certainly not HTML. So, where exactly is there a correct current paradigm (originating from mozilla.org) that describes them fully, including argument types and orders?

references:

• HTMLImageElement Mozilla documentation
• Contemporary precedent for Image() constructor use at Mozilla
• Stack Overflow related question

---

An aside: (please do not be distracted by this - locating the relevant documents as specified in the article's title is the only consideration)

This answer prompted the following examination. It is only an observation.

javascript:     alert([  Option, Image,                JSON, Math, Error,                   Array, Boolean, Date, Function,                    Number, Object, RegExp, String  ].join("\n\n"));     alert( Image.toSource() ); 

produces in FireFox:

[object Option]

[object Image]

[object JSON]

[object Math]

function Error() { [native code] }

function Array() { [native code] }

function Boolean() { [native code] }

function Date() { [native code] }

function Function() { [native code] }

function Number() { [native code] }

function Object() { [native code] }

function RegExp() { [native code] }

function String() { [native code] }

and

({})

but

Error: ({}) is not a constructor Source File: javascript:alert(new ({})); Line: 1 

Is Image a constructor or not? The answer to this would (presumably) be found in the documents that answer the question asked in this posting's title. This should emphasize the inconsistencies, anomalies and irregularities of cataloging Image and Option etc. in an appropriate document.

Answer 1

There is a distinction between JavaScript™ (the implementation of ECMAScript for DOM manipulation by Mozilla, aka Gecko) and the generic term "javascript" that is used to describe similar scripting environments in other browsers (e.g. JScript in IE).

Archaic documentation, [...] describes the existence of these constructors implicating them as intrinsic JavaScript language components, which is incorrect.

How do you come to that conclusion? JavaScript™ belongs to Mozilla so they can specify that it contains whatever they want. JavaScript™ has had an Image and Option constructor since the very beginning, other implementations have copied them so that every browser in existence has them. Such features existed before the creation of the W3C DOM interfaces and, where ubiquitous, are labelled "DOM 0", which really means were supported by Netscape Navigator and Internet Explorer at the time of DOM 1.

DOM 0 is not officially documented anywhere. HTML5 is an attempt at writing a specification for HTML and javascript as is implemented in browsers, so it includes both the Image and Option constructors and so includes DOM 0 features, but they aren't labelled or classified as such.

[...]

Yet, these constructors are clearly not intrinsic to the language specification of JavaScript

There is no published specification for JavaScript™, there is only the JavaScript documentation at Mozilla Developer Network (MDN). Also note that the documentation at MDN is a public wiki that anyone can create and edit, including you. :-)

You are mistaken in believing that the documentation at Mozilla is some kind of complete specification for JavaScript™—it isn't. Not by a long way. It is really just documentation that has been added by interested persons, mostly by poking around the browser and seeing what it does. There is also a JavaScript Reference, but you may also find that lacking.

[...]

HTMLImageElement Mozilla documentation

That link to the the Gecko DOM reference documents the JavaScript implementation of the W3C HTMLImageElementInterface which does not have an Image constructor.

Contemporary precedent for Image() constructor use at Mozilla

Which indicates that it exists, but there is no convenient place to document it. It might be best documented in the JavaScript Reference. If you wish to add it, get an MDN account (free, very easy) and add it.

Edit

There is now an Image article at MDN that links to relevant standards.

Edit 25 May 2015

The Option constructor is documented in HTML5.