JavaScript

Chapter 10: Error Handling & Debugging

ORDER OF EXECUTION

• To find the source of an error, it helps to know how scripts are processed. The order in which statements are executed can be complex; some tasks cannot complete until another statement or function has been run:

EXECUTION CONTEXT & HOISTING

• Each time a script enters a new execution context, there are two phases of activity:

BREAKPOINTS

• You can pause the execution of a script on any line using breakpoints. Then you can check the values stored in variables at that point in time.

STEPPING THROUGH CODE

• If you set multiple breakpoints, you can step through them one-by-one to see where values change and a problem might occur.

CONDITIONAL BREAKPOINTS

• You can indicate that a breakpoint should be triggered only if a condition that you specify is met. The condition can use existing variables.

HANDLING EXCEPTIONS

• If you know your code might fail, use try, catch, and finally. Each one is given its own code block.

TRY, CATCH, FINALLY

References:

• JavaScript and JQuery: Interactive Front-End Web Development by Jon Duckett Get the book

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