As long as your application doesn't encounter a problematic condition, it may still run successfully if you don't build error-handling logic into your code. However, if you don't actively handle errors and your application does encounter a problem, your users will never know why your application fails when it does.

There are different ways you can approach error handling in your application. The following list summarizes the three major options for handling errors:

• Use try..catch..finally statements. These will catch synchronous errors as they occur. You can nest your statements into a hierarchy to catch exceptions at various levels of code execution. For more information, see Using try..catch..finally statements.
• Create your own custom error objects. You can use the Error class to create your own custom error objects to track specific operations in your application that are not covered by built-in error types. Then you can use try..catch..finally statements on your custom error objects. For more information see Creating custom error classes.
• Write event listeners and handlers to respond to error events. By using this strategy, you can create global error handlers that let you handle similar events without duplicating a lot of code in try..catch..finally blocks. You are also more likely to catch asynchronous errors using this approach. For more information, see Responding to error events and status.