jsPerf.app is an online JavaScript performance benchmark test runner & jsperf.com mirror. It is a complete rewrite in homage to the once excellent jsperf.com now with hopefully a more modern & maintainable codebase.

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Can be accessed at:

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in vs typeof

Benchmark created by Timmy Willison on July 18, 2011

Preparation HTML

<div></div>

Test runner

Ready to run.

Testing in
Test		Ops/sec
in	`'getElementsByClassName' in document`	ready
typeof	`typeof document.getElementsByClassName === 'function'`	ready
property	`document.getElementsByClassName`	ready
typeof undefined	`typeof document.getElementsByClassName !== 'undefined'`	ready

Revisions

You can edit these tests or add more tests to this page by appending /edit to the URL.

Revision 1: published by Timmy Willison on July 18, 2011
Revision 2: published on August 24, 2011
Revision 3: published by Nikita Vasilyev on October 24, 2011