<!-- Do not edit this file. It is automatically generated by API Documenter. --> [Home](./index.md) > [puppeteer](./puppeteer.md) > [Protocol](./puppeteer.protocol.md) > [DOM](./puppeteer.protocol.dom.md) > [Node](./puppeteer.protocol.dom.node.md) > [systemId](./puppeteer.protocol.dom.node.systemid.md) ## Protocol.DOM.Node.systemId property `DocumentType`<!-- -->'s systemId. <b>Signature:</b> ```typescript systemId?: string; ```