00:00:00 introduction 00:00:50 example 1 00:04:00 example 2 // callback = a function that is passed as an argument // to another function. // used to handle asynchronous operations: // 1. Reading a file // 2. Network requests // 3. Interacting with databases // "Hey, when you're done, call this next." hello(goodbye); function hello(callback){ ("Hello!"); callback(); } function goodbye(){ ("Goodbye!"); }