Imagine you're at a buffet, eagerly approaching what you think is the dessert table, only to find an empty space where the chocolate cake should be. That disappointing moment? That's pretty much what happens in your code when you encounter the infamous "Cannot read properties of undefined" error. Just as you can't slice a piece of cake that isn't there, JavaScript can't read a property of an object that doesn't exist. But don't worry!

Imagine you're a postal worker sorting through a mountain of packages. Some packages are ticking suspiciously, while others are leaking mysterious liquids. As a responsible postal worker, you have two choices: deal with these problematic packages yourself (throw) or slap a big "HANDLE WITH CARE" sticker on them and pass them along to the next person in line (throws). Think of throw as actually creating an error in your program. You use it when something goes wrong and you want to stop the program.

You've just stumbled into one of the most common jQuery pitfalls. The "jquery is not defined" error is a JavaScript ReferenceError that occurs when your script tries to use jQuery functions or methods, but the jQuery library is not properly loaded or initialized. How did this happen? Probably one of three reasons: Let’s start with the last reason as that’s the easiest to fix.