JSFoo 2016

Tackling speed and performance for JavaScript

Ramanan Balakrishnan


Keep calm and track all

Submitted Aug 15, 2016

The quieter you become

With growing adoption of the web as the preferred mode of software delivery, knowing your (often anonymous) end users is becoming increasingly important. Identifying, listening and learning from them is often the best development decision that a company can make. In that vein, tracking user interactions online (using javascript trackers) will be the primary subject of this talk.

The Prime Directive has never been more applicable - you shall not interfere with the website’s performance. The focus of this talk will not be on developing amazing functionality, but rather the opposite - write javascript which is invisible to the user.

Starting with the use case of browser fingerprinting, this talk will also cover aspects of non-blocking delivery, asynchronous integration and silent operation of javascript trackers.


  1. Everyone’s a special snowflake

    With the web becoming richer everyday, it is becoming easier to identify distinct signatures in browsers. Recent research will be presented to make the case that anonymity among the crowds is no longer an easy task.

  2. You won’t feel a thing

    Convincing a kid to get his injections often requires more training than that for actually delivering the shot. So let’s also look at how we can efficiently load javascript into the browser. The emphasis will be on non-blocking, asynchronous delivery and loading of javascript packages.

  3. (quietly) Screaming into the void

    An efficient method to transmit collected data to the backend is presented. The emphasis will be on relaying information with minimal effect on actual site performance. This section also covers how modern trackers emit their data via 1x1 pixels.

  4. Keep calm and track all

    Finally, a summary of the presented techniques and tales from the trenches over the years.


Basic knowledge of how websites work (which I guess is everyone at the conference).

And an open mind, yes, definitely, an open mind.

Speaker bio

Ramanan is a software engineer at Semantics3, where he helps build analytics solutions for ecommerce. While he primarily works on enhancing the company’s intelligence capabilities, he has also been spotted diving into other aspects including development of user facing APIs. He has a keen interest in writing efficient code and always prefers removing code over writing more.

Apart from being a lockpicking enthusiast, he was previously an academic researcher investigating electromagnetics and signal processing for radar applications.




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