via ajaxian (as usual):

Aaron Hopkins of Google has released an article on Optimizing Page Load Time which came out of his experience optimizing page load times for a high-profile Ajax application.

He starts off talking about “how much I could reduce latency due to external objects. Specifically, I looked into how the HTTP client implementation in common browsers and characteristics of common Internet connections affect page load time for pages with many small objects.” Read the rest of this entry »

Hi all,

It’s been a few days since I posted. I’ve been heads down on the project to create a global javascript framework for our sites (Redball, at least). I’ve finished this work (or at least gotten it to a releasable state) and I thought I’d share an update. I plan on documenting it extensively and providing a lot of examples (and teaching it) in the near future, but for those of you who are curious, you can peruse the library now. It’s mostly stable (we’re still tweaking and adding things) and you can just download them and read them if you want to see what’s in them.

They include a lot of functionality, are highly extendable, easily debuggable, and hopefully will be useful. The current framework file is about 30K, but Andy just turned me on to a more efficient javascript compressor that will bring that down to 19K. I can’t express how awesome it is to have this thing going out and it managing to pack in so much functionality in such a small package. Read the rest of this entry »

MooTools continues to impress me. Check out the Class.implement and Class.extend functionality in this great article from Cory Hudson (there are numerous code examples).

mootools implements a class inheritance scheme that is inspired by Dean Edwards’ wonderful Base class. Creating a class is similar to Prototype, but now you don’t ever have to think about the prototype object when you define the class…

…mootools supports multiple inheritance in a Ruby mixin style with the Class.implement() method. Using the implement method of an existing class, that class can inherit methods and properties from another class or object. Unlike Class.extend(), the implement method is called on the class you are modifying, not on the object being copied. This method can be used to support multiple inheritance.

And here’s another article from Cory on MooTools numerous helpful utility functions:

The new mootools JavaScript framework has quickly impressed me with its design and usefulness. The library was clearly written to meet real programmers’ needs while working in JavaScript. Just take a look at some of the new utility functions and methods it provides.

Note: This article covers functions and methods found in the Array.js and Function.js modules of mootools.

Well crap. 1) I love the mad4milk guys (makers of moo.fx, moo.ajax, moo.dom, prototype.lite). 2) their new framework looks AWESOME. 3) as always, their libraries are SUPER TINY.

But damn, now I have to learn something new, and maybe rewrite a bunch of crap. This is the problem with javascript. Still, when Prototype + Scriptaculous is 100K, you gotta admire their ability to crank something out in under 20K that will get you nearly the same thing.

The Mad4Milk team (the minds that brought the world moo.fx) have unleashed a brand new, very impressive Javascript library out onto the web – MooTools.

mootools is a very compact, modular, Object-Oriented javascript framework. Its unique design makes it extremely crossbrowser, easy to use, and a snap to extend with your own code. It comes with a choice of more than fifteen scripts, plugins and addons, including Effects (moo.fx) Ajax (moo.ajax), Dom Navigator (moo.dom), Drag and Drop, Sortable lists, cookies Manager and many more.

There aren’t any demos of the functionality quite yet (as of the date of this post), but you can download the first release of thise powerful little tool.

You can also check out what Jonathan Snook has to say about it, having already downloaded and worked with it a bit. He’s also created a simple tutorial on using the new library to create a drag-and-drop example.

via ajaxian – note that closures are one big cause of memory leaks…

Morris Johns has gone though and written a detailed explanation of closures by example:

If everything seems completely unclear then the best thing to do is to play with t e examples. Reading an explanation is much harder than understanding example
My explanations of closures and stack-frames etc are not technically correct – they are gross simplifications intended to help understanding. Once the basic idea is grokked, you can pick up the details later.

Final points:

• Whenever you use function inside another function, a closure is used.
• Whenever you use eval() inside a function, a closure is used. The text you eval can reference local variables of the function, and within eval you can even create new local variables by using eval(‘var foo = ‘
• When you use Function() inside a function, it does not create a closure. (The new function cannot reference the local variables of the function calling Function()).
• A closure in JavaScript is like keeping a copy of the all the local variables, just as they were when a function exited.
• It is probably best to think that a closure is always created just on entry to a function, and the local variables are added to that closure.
• A new set of local variables is kept every time a function with a closure is called (Given that the function contains a function declaration inside it, and a reference to that inside function is either returned or an external reference is kept for it in some way).
• Two functions might look like they have the same source text, but have completely different behaviour because of their ‘hidden’ closure. I don’t think JavaScript code can actually find out if a function reference has a closure or not.
• If you are trying to do any dynamic source code modifications ( for example: myFunction = Function(myFunction.toString().replace(/Hello/,’Hola’)); ), it won’t work if myFunction is a closure (Of course, you would never even think of doing source code string substitution at runtime, but…).
• It is possible to get function declarations within function declarations within functions – and you can get closures at more than one level.
• I think normally a closure is the term for both the function along with the variables that are captured. Note that I do not use that definition in this article!
• I suspect that closures in JavaScript differ from those normally found in functional languages.