StyleSheetList

CSS object model css-object-model

Baseline: Widely available on the web, in every major browser since Sep 2015, and long enough to count on (since Mar 2018).

niso: Partial 55%. 123 of 221 subtests pass, by system: Linux 55%, macOS 55%. Engines: QuickJS, the engine niso's WPT run uses; Node and Porffor have no recorded run. WPT results recorded at f3b4fa8, 2026-11-10; web-features 3.45.0. WPT tests · niso's support · CSS, CSSConditionRule, CSSGroupingRule, CSSMediaRule

StyleSheetList is an interface in idl/cssom.webidl, exposed in Window. What it does is on MDN; this page says what niso has of it.

Status

The web features its members belong to, each with its Baseline status on the web and how much of the feature’s WPT suite passes in niso (see Web platform support).

Feature	On the web	In niso	Members
CSS object model	Widely available	Partial 55% 123 of 221 subtests pass	3

Members

item()

operation

getter CSSStyleSheet? item(unsigned long index);

int32_t niso_style_sheet_list_item(niso_dom* dom, niso_handle self, uint32_t index, niso_handle* out);

length

attribute

readonly attribute unsigned long length;

int32_t niso_style_sheet_list_get_length(niso_dom* dom, niso_handle self, uint32_t* out);