Google Closure: How not to write JavaScript At the Edge of the Web conference in Perth last week I got to catch up with Dmitry Baranovskiy, the creator of the Raphaël and gRaphaël JavaScript libraries. Perhaps the most important thing these libraries do is make sophisticated vector graphics possible in Internet Explorer, where JavaScript performance is relatively poor. Dmitry, therefore, has little patience for poorly-written JavaScript like the code he found in Google’s just-released Closure Library. Having delivered a talk on how to write your own JavaScript library (detailed notes) at the conference, Dmitry shared his thoughts on the new library over breakfast the next morning. “Just what the world needs—another sucky JavaScript library,” he said. For the rest of the day, to anyone who would listen, Dmitry cited example after example of the terrible code he had found when he went digging through Closure. “I’ll make you a deal,” I told him. The Slow Loop From array.js, line 63: for (var i = fromIndex; i < arr.length; i++) {
JavaScript Tutorial A JavaScript Module Pattern Eric Miraglia (@miraglia) is an engineering manager for the YUI project at Yahoo. Eric has been at Yahoo since 2003, working on projects ranging from Yahoo Sports to YUI. For the past several years, Eric and his colleagues on the YUI team have worked to establish YUI as the foundation for Yahoo’s frontend engineering work while open-sourcing the project and sharing it with the world under a liberal BSD license. Eric is an editor and frequent contributor to YUIBlog; his personal blog is at ericmiraglia.com. Prior to working at Yahoo, Eric taught writing at Stanford and elsewhere and led frontend engineering teams at several startups. Global variables are evil. Douglas Crockford has been teaching a useful singleton pattern for achieving this discipline, and I thought his pattern might be of interest to those of you building on top of YUI. 1. YAHOO.namespace("myProject"); This assigns an empty object myProject as a member of YAHOO (but doesn’t overwrite myProject if it already exists). 2.
css3-mediaqueries-js - Project Hosting on Google Code css3-mediaqueries.js by Wouter van der Graaf is a JavaScript library to make IE 5+, Firefox 1+ and Safari 2 transparently parse, test and apply CSS3 Media Queries. Firefox 3.5+, Opera 7+, Safari 3+ and Chrome already offer native support. UPDATE: Google discontinued the downloads section. Download newest version 1.0 from here: Usage: just include the script in your pages. (And you should combine and compress with other scripts and include it just before </body> for better page speed - but you already knew that). Write your media queries like you would for browsers with native support. Note: Doesn't work on @import'ed stylesheets (which you shouldn't use anyway for performance reasons). Happy media querying!
Understanding JavaScript’s this keyword | JavaScript, JavaScript (In Portugese) The JavaScript this keyword is ubiquitous yet misconceptions abound. What you need to know Every execution context has an associated ThisBinding whose lifespan is equal to that of the execution context and whose value is constant. There are three types of execution context: global, function and evaluation. Here’s a tabular summary followed by a little more detail, and some examples: 1. 2. a) Invoke as a methodthis is the baseValue of the property reference b) Invoke as baseless function callthis is the global object (or undefined in strict mode) The same applies to self invoking functions: c) Invoke using Function.prototype.callthisis passed by argument d) Invoke using Function.prototype.applythis is passed by argument e) Invoke a constructor using newthis is the newly created object 3. What you might want to know This section explores the process by which this gets its value in the functional context – using ECMA-262 version 5.1 as a reference. from ECMA 5.1, 11.1.1 1. 1. In full…
base2 - Project Hosting on Google Code Because this library is standards-based it means that you don’t have to learn a new API. It uses standard (DOM, ECMAScript) properties and methods throughout which also means that there is no need for a lot of accompanying documentation. base2 is a lightweight library that irons out all the annoying differences in JavaScript implementations. It provides the additional functionality from JavaScript 1.6+ that only Mozilla browsers implement. It also adds some features from ES4. A fast implementation of the Selectors API Fixes broken browser implementations of the DOM events module including document.createEvent(), dispatchEvent(), addEventListener(), etc Supports DOMContentLoaded Fixes getAttribute()/setAttribute()/hasAttribute() (Internet Explorer) Implements getElementsByClassName() Implements a few other useful DOM methods like getComputedStyle() and compareDocumentPosition() Supports a variety of browsers including ancient browsers like IE5.0 (Windows and Mac) Current version: 1.0.2
Sylvester - Vector and Matrix math for JavaScript Badass JavaScript evercookie - virtually irrevocable persistent cookies samy's home page || follow my twitter || email me || samy kamkar October 11, 2010: Reported on the front page of the New York Times Find the latest details, code, and implementations on github @ Cookie found: uid = currently not set Click to create an evercookie. Don't worry, the cookie is a random number between 1 and 1000, not enough for me to track you, just enough to test evercookies. Now, try deleting this "uid" cookie anywhere possible, then or evercookie is written in JavaScript and contains portions in Java, SWF/ActionScript (Flash) and C# (Silverlight). What is the point of evercookie? csshack, best website ever See CONTACT. Questions or comments, email me: code@samy.pl.
37signals' Chalk Dissected Update 2010-11-05: I dove into the JavaScript a little and explained most of it. Sam Stephenson tweeted that Chalk is written in CoffeeScript and compiled on the fly when served using Brochure. That's hot! (for those unaware Sam Stephenson works at 37signals, and is also the man behind Prototype.) 37signals recently released a blackboard web app for iPad called Chalk. It includes Thomas Fuchs new mobile JS framework Zepto, a few images, iOS SpringBoard icon, and of course HTML, CSS, and JavaScript. The manifest is a nice summary of the contents, and allows browsers to cache the app for offline use. CACHE MANIFEST / /zepto.min.js /chalk.js /images/background.jpg /images/chalk.png /images/chalk-sprites.png /images/chalk-tile-erase.jpg /images/chalk-tile-red.png /images/chalk-tile-white.png /stylesheets/chalk.css Not much there, just 10 requests to fetch the whole thing. 11 including the manifest. 2k, 61 lines. 10 of which are Google Analytics JavaScript. Onward. Zepto Display (CSS & Images)
Organizing A jQuery Application - Jupiter JavaScript Consulting Earlier this week, I realized that every organizing-a-jQuery-application blog, article, and conference talk misses the most important lesson on how to organize a jQuery app. They talk about how to organize an individual widget or piece of functionality, but not how you can break up an application into logically separate and testable components. Separation of concerns is the bedrock of software engineering. It is the best way to achieve a quality, error free, and maintainable project. Think about it … If your code’s logic is isolated, how much damage does making an incorrect decision do? Very little! The secret to building large apps is NEVER build large apps. This article shows how to do this elegantly with JavaScriptMVC 3.0 (which was created with this pattern in mind). Srchr The Srchr app makes searches using multiple services and saves the searches between page loads. Install Srchr To install our srchr app: Download And Unzip JavaScriptMVC Install Srchr . Srchr’s Sweetness Srchr.History
batiste/sprite.js - GitHub Face Detection jQuery Plugin