During some interesting discussions on Twitter yesterday I found that there is now more than ever a confusion about JavaScript dependence in web applications and web sites. This is a never ending story but it seems to me to flare up ever time our browsing technology leaps forward. I encountered this for the first time back in the days of DHTML. We pushed browsers to their limits with our lovely animated menus and 3D logos (something we of course learned not to do again, right?) and we were grumpy when people told us that there are environments out there where JavaScript isn’t available....

Since its birth in 1994, Javascript has come a long way. Today it’s one of the most popular programming languages on the web because of high popularity of AJAX based web-applications. Also the rise of micro-frameworks such as jQuery (also Prototype, Moo Tools etc) which have reduced dramatically the complexity of code developers needed to write, it is well tested, has a ton of plug-ins, has a large development community and reduced development time.And lately even Server-Side JavaScript (SSJS) like Node.js which allows you to create high performance, real-time web applica...

Recently people presented arguments for and against using CoffeeScript. I felt the argument against was pointless and obviously wrong, but I couldn't figure out why, and I thought the counterargument for was kind of toothless and irrelevant. I've figured out the real issue.The real argument for CoffeeScript is that JavaScript is not really a language.Years ago I read something which explained, in my opinion, why Lisp has never achieved the mainstream adoption its passionate advocates believe it deserves. Lisp projects experience a degree of balkanization because everything is left wide open; y...

On this page I explain the two advanced event registration models:W3C’s and Microsoft’s. Since neither is cross–browser supported,their use is, for the moment, deprecated.W3C and Microsoft have both developed their own event registration modelto replace Netscape’straditional model. Though I’m notimpressed by the Microsoft model, W3C’s is very good, except for onecrucial vagueness.Unfortunately few browsers support it at the moment.W3CW3C’sDOM Level 2 Event specification pays careful attentionto the problems of the traditional model. It offers a ...

I decided to write a little article to discourage an unfortunately common pattern in Node.JS modules (and browser JavaScript, to a lesser extent) that can boil down to these two examples:// A:function myFunction () {  if (somethingWrong) {    throw 'This is my error'  }  return allGood;}and// B: async Node.JS-style callback with signature `fn(err, …)`function myFunction (callback) {  doSomethingAsync(function () {    // …    if (somethingWrong) {      callback('This is my error')    } else {    &nb...

At Khan Academy we've been investigating teaching Computer Science to students in some new and interesting ways. The most interesting aspect of which is that we're likely going to be teaching them JavaScript as their first language.We're in a very unique position as we're primarily aiming to teach students who've been through our previous math and science-centric curriculum. Because of this we can create some rather compelling exercises and projects that never would've been feasible otherwise.The prospect of teaching the JavaScript language as a first language is actually really exciting. Teac...

There’s no denying it. I’m just to damn lazy to be an HTML developer. This really sunk in when I looked at a tutorial for doing a jQuery Lightbox – for a client project. The tutorial was titled “Super Simple Lightbox with CSS and jQuery” but after reading it over I thought a better title would be “A really freaking hard tutorial on the inane intricacies of doing something that looks simple but in reality is a skein of HTML, Javascript and CSS that no one except an HTML Jedi Master could every come up with “.I must say that I have a totally refreshed...

We've seen some neat interactive HTML5 infographics before -- but the periodic table, for example, doesn't really care that much about time.Visual representation of time introduces numerous complications. Traditional ways of representing time visually were, roughly speaking, translations of dimension-type, from temporal to spatial; the mapping selected would depend on what kind of temporal relation was meaningful for the particular application. For example, circles represent cyclical behavior; lines represent development; trees represent evolutionary history; and so forth. New media change the...