One of the more subtle yet awesome changes that HTML5 brings, applies to the id attribute. I already tweeted about this a few months ago, but I think this is interesting enough to write about in more than 140 characters.

The following article, written by John-David Dalton and yours truly, was published as part of the Performance Calendar series in 2010.

HTML5 standardizes the oninput event handler, which should be used to detect user input in JavaScript. Sure, you could use onkeydown or onkeyup instead, but those were never really designed for this particular use case, and it shows.

By now, everyone knows how to detect and use localStorage. However, I’ve been using a seemingly unconventional (but slightly more efficient) technique to do so. Since I haven’t seen it documented anywhere else, here goes!

As a follow-up to the post documenting a few popular HTML element + attribute notations, here’s a similar one about JavaScript.

Having recently written about character references in HTML, I figured it would be interesting to look into JavaScript character escapes as well.

Does JavaScript use UCS-2 or UTF-16 encoding? Since I couldn’t find a definitive answer to this question anywhere, I decided to look into it. The answer depends on what you’re referring to: the JavaScript engine, or JavaScript at the language level.

Did you know var π = Math.PI; is syntactically valid JavaScript? I thought this was pretty cool, so I decided to look into which Unicode glyphs are allowed in JavaScript variable names, or identifiers as the ECMAScript specification calls them.

Fun fact: var foo = { H̹̙̦̮͉̩̗̗ͧ̇̏̊̾Eͨ͆͒̆ͮ̃͏̷̮̣̫̤̣Cͯ̂͐͏̨̛͔̦̟͈̻O̜͎͍͙͚̬̝̣̽ͮ͐͗̀ͤ̍̀͢M̴̡̲̭͍͇̼̟̯̦̉̒͠Ḛ̛̙̞̪̗ͥͤͩ̾͑̔͐ͅṮ̴̷̷̗̼͍̿̿̓̽͐H̙̙̔̄͜: 42 }; is valid JavaScript. It may not be immediately obvious, but the real surprise here is that the Cthulhu-esque property name is not surrounded by quotes. Intrigued by this, and having written about the similar topic of JavaScript identifiers before, I decided to look into valid property names in JavaScript. When do they need to be quoted? When can the quotes be omitted? And in which cases can dot notation be used instead of bracket notation to get or set a property based on its name?

Are you using MySQL’s utf8 charset in your databases? In this write-up I’ll explain why you should switch to utf8mb4 instead, and how to do it.

Looking for a list of all reserved words in JavaScript? You’ve come to the right place. I recently needed such a list myself, but ended up comparing the reserved keywords in all ECMAScript versions as well. The result is listed below, for future reference.

The way JavaScript handles Unicode is… surprising, to say the least. This write-up explains the pain points associated with Unicode in JavaScript, provides solutions for common problems, and explains how the ECMAScript 6 standard improves the situation.

It’s trivial to find colliding passwords when hashing with PBKDF2-HMAC-anything. This post explains why that is.

By default, composing a new email in Gmail results in an HTML email under the hood. It’s possible to opt-out of that and use plain text email instead, but that leads to some problems.

ES2015 updates the grammar for identifiers. This affects a number of things, but most importantly, identifiers can be used as variable names, and identifier names are valid unquoted property names. This post describes the observable changes compared to the old ES5 behavior.

ES2018 adds support for Unicode property escapes of the form p{…} and P{…} to JavaScript regular expressions. This article explains what Unicode property escapes are, how they work, and why they’re useful.

This article highlights what’s happening in the world of JavaScript regular expressions right now. Spoiler: it’s quite a lot — there are more RegExp-related proposals currently advancing through the TC39 standardization process than there have been updates to RegExp in the history of ECMAScript!

Compared to using promises directly, not only can async and await make code more readable for developers — they enable some interesting optimizations in JavaScript engines, too! This write-up is about one such optimization involving stack traces for asynchronous code.

This article describes some key fundamentals that are common to all JavaScript engines — and not just V8, the engine the authors work on. As a JavaScript developer, having a deeper understanding of how JavaScript engines work helps you reason about the performance characteristics of your code.

This article explains JavaScript engine optimization pipeline trade-offs, and describes how engines such as V8 speed up accesses to prototype properties. As a JavaScript developer, having a deeper understanding of how JavaScript engines work helps you reason about the performance characteristics of your code.

The globalThis proposal introduces a unified mechanism to access the so-called “global object” a.k.a. “the global” in any JavaScript environment. It sounds like a simple thing to polyfill, but it turns out it’s pretty hard to get right.

As Chennai still grapples with scanty containment zone management and spike in the number of positive cases, other districts in the state have succeeded in flattening the curve using effective containment strategy.

All the 356 passengers who arrived from Dubai by the first two rescue flights were sent to quarantine centres after their throat and nasal swabs were taken at Chennai airport on Saturday. The first flight IX 612 had 179 passengers and the second 177.

With the onset of this pandemic, policyholders should now take the next crucial step of understanding how to go about filing a health insurance claim