JavaScript Performance MythBusters™ (via JSPerf)

Moderated by:
Lindsey Simon (Google)
Nicholas Zakas (Box), Chris Joel (Cloudflare), Kyle Simpson (Getify)
Web Performance Mission City B4
Average rating: ****.
(4.25, 4 ratings)

JavaScript is everywhere from mobile phones and tablets to e-readers and TVs. With such a wide range of supported environments developers are often looking for an easy way to compare the performance between
snippets, browsers, and devices., a site for community driven JavaScript benchmarks, was created to help devs do just that.
Join Mathias Bynens from, Chris Joel from and Lindsey Simon from Google/Browserscope in this panel discussion on some of the best dev-created benchmarks and most interesting practices debunked by real-world tests.
Will help you answer:

  • Which so-called best practices should I avoid?
  • What are the most interesting JS tests on JSPerf and in the wild on Cloudflare?
  • String concatenation vs Array.join – should you care?
  • Can we really test JavaScript performance in the wild with accuracy?
Photo of Lindsey Simon

Lindsey Simon


Lindsey Simon is a Front-End Developer at Twist, a mobile startup in San Francisco. Simon hails from Austin where he worked at startups, taught computing at the Griffin School, and was the webmaster for years at the Austin Chronicle.

Photo of Nicholas Zakas

Nicholas Zakas


Nicholas C. Zakas is a staff software engineer at Box, author, and speaker. He worked at Yahoo! for almost five years, where he was front-end tech lead for the Yahoo! homepage and a contributor to the YUI library. He is the author of Maintainable JavaScript (O’Reilly, 2012), Professional JavaScript for Web Developers (Wrox, 2012), High Performance JavaScript
(O’Reilly, 2010), and Professional Ajax (Wrox, 2007). Nicholas is a strong advocate for development best practices including progressive enhancement, accessibility, performance, scalability, and maintainability. He blogs regularly at and can be found on Twitter via @slicknet.

Photo of Chris Joel

Chris Joel


I have been building web applications targeting browsers and mobile devices for almost ten years. I am presently employed to build tools and libraries that artificially enhance the client-side loading speed of arbitrary websites when viewed on arbitrary devices. I write code that enables applications to be aesthetically pleasing, intuitively usable and fast all at once, and the exercise of writing this code has given me many unique insights about JavaScript performance.

Photo of Kyle Simpson

Kyle Simpson


Kyle Simpson is an evangelist of the Open Web, passionate about all things JavaScript. He writes, speaks, teaches, and contributes to OSS.


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