[Home](./index.md) > [puppeteer](./puppeteer.md) > [Protocol](./puppeteer.protocol.md) > [CSS](./puppeteer.protocol.css.md) > [CSSKeyframeRule](./puppeteer.protocol.css.csskeyframerule.md) > [styleSheetId](./puppeteer.protocol.css.csskeyframerule.stylesheetid.md) ## Protocol.CSS.CSSKeyframeRule.styleSheetId property The css style sheet identifier (absent for user agent stylesheet and user-specified stylesheet rules) this rule came from. Signature: ```typescript styleSheetId?: StyleSheetId; ```