Functions are blocks of code that can be called by other code or can be triggered by user input or events. The function performs a set of tasks and returns a result. Functions commonly use parameters and variables to allow information to be passed into them and are usually declared using the function keyword followed by parentheses.
In addition to using the browser’s built-in error messages, it can also be helpful to use a debugging tool such as Chrome DevTools or Firebug. These tools allow you to step through your code line by line, inspect variables, and view the call stack to help you identify the source of the problem. With these tools, you can quickly identify and fix errors in your code, saving you time and frustration.