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Function Options

You can also determine which functions are profiled. To set an entire file so that it won’t be profiled,

right-click on the file in the Loaded Scripts view and select File Options

Don’t Profile Contained

Functions. If you want to disable profiling for a single function, right-click on the function in the Loaded

Scripts view and select Function Options

Don’t Profile.

Summary

This chapter introduced the many aspects of errors and error handling in JavaScript. The

onerror

event

handler was covered, including the creation of your own error-message windows. You also learned how

to use the

try...catch

statement to trap errors in progress. An in-depth discussion of the

Error

object

followed, introducing you to how you can throw your own JavaScript errors.

Next, several debugging techniques were discussed, ranging from using alerts and Java console messages

to throwing your own errors. You also learned how to create your own

assert()

function to make throw-

ing your own errors easier.

Finally, you were introduced to the JavaScript debuggers for Internet Explorer and Mozilla. You learned

how to download, install, and run each debugger in its browser, as well as how to use the debugger to

set breakpoints and step through code.

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Error Handling

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