Basic Properties & Methods
document.title → Get or set the page title.document.body → Access the <body> element.document.documentElement → Access the <html> element.document.head → Access the <head> element.document.referrer → Get the referrer URL.document.readyState → Get the document loading state (loading / interactive / complete).document.hasFocus() → Check if the document is active.document.visibilityState → Check if the page is visible (visible / hidden).document.domain → Get or set the current domain (for cross-subdomain communication).document.activeElement → Returns the currently focused element.
console.log(document.title);
document.title = "New Page Title";
console.log(document.activeElement); // Logs the element currently in focus
Selecting & Modifying Elements
document.getElementById(id) → Select an element by ID.document.querySelector(selector) → Select the first matching element.document.createElement(tagName) → Create a new element.document.createTextNode(text) → Create a text node.document.appendChild(node) → Append an element.
const div = document.createElement("div");
div.textContent = "Hello, Document!";
document.body.appendChild(div);
Advanced Document APIs