CSSStyleRule

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

CSSStyleRule is an interface in idl/cssom.webidl, inheriting CSSGroupingRule, 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

selectorText

attribute

attribute DOMString selectorText;

int32_t niso_css_style_rule_get_selector_text(niso_dom* dom, niso_handle self, niso_str* out);
int32_t niso_css_style_rule_set_selector_text(niso_dom* dom, niso_handle self, const char* value, size_t value_len);

style

attribute

[SameObject, PutForwards=cssText] readonly attribute CSSStyleDeclaration style;

int32_t niso_css_style_rule_get_style(niso_dom* dom, niso_handle self, niso_handle* out);

Not in niso yet

Members the web has, by the BCD keys web-features 3.45.0 lists, that idl/ doesn’t declare. The list is partial: web-features lists only the keys it maps to a feature.

• cssRules (Nesting)
• deleteRule (Nesting)
• insertRule (Nesting)
• styleMap (CSS typed object model)