{{APIRef()}}
The HTMLCollection
interface represents a generic collection (array) of elements (in document order) and offers methods and properties for selecting from the list.
HTMLCollection
for historical reasons (before DOM4, collections implementing this interface could only have HTML elements as their items).An HTMLCollection
in the HTML DOM is live; it is automatically updated when the underlying document is changed.
Properties
- {{domxref("HTMLCollection.length")}} {{readonlyInline}}
- Returns the number of items in the collection.
Methods
- {{domxref("HTMLCollection.item()")}}
-
Returns the specific node at the given zero-based
index
into the list. Returnsnull
if theindex
is out of range. - {{domxref("HTMLCollection.namedItem()")}}
-
Returns the specific node whose ID or, as a fallback, name matches the string specified by
name
. Matching by name is only done as a last resort, only in HTML, and only if the referenced element supports thename
attribute. Returnsnull
if no node exists by the given name.
Usage in JavaScript
In JavaScript, code that accesses HTMLCollection
object, in order to get an item of the given HTMLCollection
, the square bracket syntax can be used instead of directly calling the item()
or namedItem()
methods. Numeric values in the square brackets will work the same way as item()
, string values will work the same way as namedItem().
For example, assuming there is one <form>
element in the document and its id
is "myForm"
:
var elem1, elem2; // document.forms is an HTMLCollection elem1 = document.forms[0]; elem2 = document.forms.item(0); alert(elem1 === elem2); // shows: "true" elem1 = document.forms["myForm"]; elem2 = document.forms.namedItem("myForm"); alert(elem1 === elem2); // shows: "true"
Browser compatibility
Different browsers behave differently when there are more than one elements matching the string used as an index (or namedItem
's argument). Firefox 8 behaves as specified in DOM 2 and DOM4, returning the first matching element. WebKit browsers and Internet Explorer in this case return another HTMLCollection
and Opera returns a {{domxref("NodeList")}} of all matching elements.
Specification
See also
- {{domxref("NodeList")}}
- {{domxref("HTMLOptionsCollection")}}