CSS Object Model 是一组允许用JavaScript操纵CSS的API。 它是继DOM和HTML API之后，又一个操纵CSS的接口，从而能够动态地读取和修改CSS样式。
API参考
AnimationEventCaretPositionCSSCSSCharsetRuleCSSConditionRuleCSSCounterStyleRuleCSSFontFaceRuleCSSFontFeatureValuesMapCSSFontFeatureValuesRuleCSSGroupingRuleCSSImportRuleCSSKeyframeRuleCSSKeyframesRuleCSSMarginRuleCSSMediaRuleCSSNamespaceRuleCSSPageRuleCSSRuleCSSRuleListCSSStylesheetCSSStyleDeclarationCSSSupportsRuleCSSVariablesMapCSSViewportRuleElementCSSInlineStyleGeometryUtilsGetStyleUtilsLinkStyleMediaListMediaQueryListPseudoElementScreenStylesheetStylesheetListTransitionEvent
CSSOM相关规范也扩展了其他几个接口：
Document, Window, Element, HTMLElement, HTMLImageElement, Range, MouseEvent, and SVGElement.
教程
- Determining the dimensions of elements (这篇文档可能有点过时，因为它是在的DHTML/Ajax时代写的).
- Managing screen orientation
规范
| 规范 | 进度 | 评价 |
|---|---|---|
| CSS Object Model (CSSOM) | Working Draft | |
| CSS Object Model (CSSOM) View Module | Working Draft | |
| Screen Orientation API | Working Draft | |
| CSS Fonts Module Level 3 | Candidate Recommendation | |
| CSS Animations | Working Draft | |
| CSS Transitions | Working Draft | |
| CSS Custom Properties for Cascading Variables Module Level 1 | Candidate Recommendation | |
| CSS Conditional Rules Module Level 3 | Candidate Recommendation | |
| CSS Device Adaptation | Working Draft | |
| CSS Counter Styles Level 3 | Candidate Recommendation |
浏览器兼容性
近几年所有的这些新特性正在一点一点的向不同的浏览器内添加，不过这确实是一个很复杂无法用简单表格总结的过程。如果具体项目中需要用到，请详细的检查接口的可用性。