JavaScript Full Guide 1. What is JavaScript? JavaScript (JS) is a programming language used to make websites interactive . If a website is: Just text → HTML Styled → CSS Interactive (clicks, animations, login, updates) → JavaScript Example: Clicking a button Showing popup messages Validating login form Updating content without refreshing page JavaScript runs inside the browser (Chrome, Firefox, etc.). 2. How JavaScript Works When a user opens a website: HTML loads (structure) CSS loads (design) JavaScript runs (logic & actions) JavaScript is like the brain of the website 3. Where to Write JavaScript? There are 3 ways: 1. Inside HTML file <script> console . log( "Hello JavaScript" ); </script> 2. External file (best practice) <script src = "script.js" ></script> 3. Inline (not recommended) <button onclick = " alert ( 'Hi' ) " > Click </button> 4. Variables (...