A short note about errors before we proceed to the next session.
When you are learning a new programming language it takes time to understand its syntax. Your code might have a few bugs; it’s okay as long as you know how to correct them.
They might try to call a variable that is not yet defined.
Solution: Remember to always initialize all variables you expect to use in the script.
Forgetting the starting or ending quote or parenthesis as in a method or function.
Solution: Place the opening and ending parenthesis or quotes together, then write the code/text between them.
Using a property or method that does not belong to an object, for example, using document.alert() instead of window.alert().
Solution: You don’t have to learn each and every object’s properties and methods at the very start… you’ll get the hang of it all gradually.
The first product to be scanned using a bar code was a pack of Wrigley's chewing gum at Marsh Supermarket in Troy, Ohio. [more...]