1. PhoneGap is a framework that allows developers to build mobile apps using HTML, CSS, and JavaScript instead of platform-specific languages. It works by wrapping web pages in a native container so they can access native device functions and be deployed to app stores.
2. The document discusses PhoneGap features like access to device APIs, cross-platform deployment, and debugging tools. It also covers setting up the PhoneGap development environment and creating a basic "Hello World" app.
3. The document provides code examples for the app manifest, JavaScript to access device functions, and HTML/CSS pages. It also discusses PhoneGap advantages like multiple platform support and disadvantages like lack of support for all native features.