HTMLCollection - Web APIs | MDN
Instance properties
HTMLCollection.lengthRead only-
Returns the number of items in the collection.
Instance methods
HTMLCollection.item()-
Returns the specific element at the given zero-based
indexinto the list. Returnsnullif theindexis out of range.An alternative to accessing
collection[i](which instead returnsundefinedwheniis out-of-bounds). This is mostly useful for non-JavaScript DOM implementations. 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 thenameattribute. Returnsnullif no node exists by the given name.An alternative to accessing
collection[name](which instead returnsundefinedwhennamedoes not exist). This is mostly useful for non-JavaScript DOM implementations.
Usage in JavaScript
HTMLCollection also exposes its members as properties by name and index. HTML IDs may contain : and . as valid characters, which would necessitate using bracket notation for property access. Currently, an HTMLCollection object does not recognize purely numeric IDs, which would cause conflict with the array-style access, though HTML does permit these.
For example, assuming there is one <form> element in the document and its id is myForm:
js
let 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"
elem1 = document.forms["named.item.with.periods"];
Specifications
| Specification |
|---|
| DOM # interface-htmlcollection |