The document provides code examples for various JavaScript concepts:
1. Embedding JavaScript in HTML to display alerts and write to the document.
2. Examples of conditional statements like if/else, if/else if, and switch statements.
3. Code for different loop structures - for, while, and do-while loops.
4. Demonstrations of string methods like replace, toLowerCase, indexOf and more.
5. Event handlers - onfocus, onload, onblur, onsubmit and how to trigger functions.