• Switched QuerySelector engine to Sizzle 1.0
• querySelector/querySelectorAll can now be run on any element (via Selectors API)
• IE 8 does not like setAttribute on type elements. Reverting to DOM 1 method.
• Fixed minor assertion bug in Require.js

Update 2: This code is released to the public domain. You can use, modify, remix as you see fit.

Behold, fixed positioning on iPhone! http://doctyper.com/stuff/iphone/fixed/

Here’s a video for those without iPhones. This is running in the iPhone Simulator bundled with the SDK. Note that the animation is much choppier on an actual iPhone.

With the release of iPhone OS 2.0 came some great improvements over previous Mobile Safari versions. CSS animations are in (though buggy), as well as native touch events like touchstart, touchend, gesturechange, etc.

I played around with these new goodies while hunting for improvements to build into Pickleview. The most fascinating change to me was that you can now prevent the default behavior of elements with a simple preventDefault() call. It allows a user to drag an element around the screen without having to worry about the viewport wobbling about.

I grew curious as to what I could specifically call this on, and started testing out several elements. Turns out you can preventDefault on everything in the DOM, including the body element. This seemed incredibly useless for no other reason than the terrible usability it would bring if you couldn’t scroll the viewport. Then the proverbial light bulb went off: fixed positioning!

First, let’s recap why fixed positioning does not work off-the-bat. Mobile Safari uses a viewport to show you websites. Imagine a book in front of you. Take a piece of paper, cut a 320×416 square in it, and lay it over the book. To read the book, move the paper around and position the hole over the words you want to see. This is exactly what Mobile Safari’s viewport is doing. When you flick and scroll, you’re moving the viewport around while the website behind it stays static.

This renders fixed positioning null and void on iPhone. An element that has its position fixed is affixed to the body, not the viewport. So it is actually working as intended, though most people would prefer it attached to the viewport.

There are workarounds in the wild, but these are inelegant. You can reposition an element onscroll, but a scroll event in Mobile Safari is only fired after scrolling has stopped. This results in an evident “glitch” since you have to a) flick to your desired position, throwing the element off-screen, and b) wait for the element to reappear in the viewport after scrolling has stopped.

By disabling the default scroll behavior on the body element, you essentially glue the viewport down to its initial starting point, where it’s unable to go anywhere. This limits the viewport to exactly 320×416 pixels of space to show you. In this state, you have a perfectly useless experience.

This is where it gets interesting. In order to re-enable scrolling, I needed to only make the content area scrollable (think iframe, with header and footer above and below it). The touch and gesture events gives access to X/Y values, as well as timers and offset values. So by logging these and incrementing the top offset of the content area, we can create a scrollable block that does not affect the header or footer elements. A little spit and polish later: voila!

It’s pretty evident from my proof-of-concept that CSS animations need a lot of work. They’re promised to be “hardware-accelerated”, but there’s little proof of this. Most animations glitch, some to the point of non-use. The scrolling isn’t particularly smooth and even something as simple as animating a ‘top’ CSS property takes its toll. Still it’s usable, though I hope later Mobile Safari builds will address these issues.

If you’re interested, I’ve bundled together the source files for my proof-of-concept. Grab ‘em here.

Naturally, this sent me on the hunt to see if it was at all possible. A furious Google search led me to a comment by Dean Edwards (who else?). He suggested throwing yourself out of the loop and wrapping the throw in a try catch statement to silence the throw. Like so:

var array = [1, 2, 0, 3, 4, 5];
try {
  array.forEach(function(item) {
    if (item === 0) {
      throw new Error(); // Simulated break
    }
    console.log(item);
  });
} catch (e) {}

That does the trick. Fellow developer/comrade Lenny Burdette pointed out that this was exactly the method Prototype uses to break their own custom loops.

But of course, there’s caveats. With Prototype, you merely have to call $break to have it automate this for you. With Flow, you’re exposed to the elements and need to handle it yourself. It’s a neat trick, but quite honestly it’s not very user friendly, and looks a bit unwieldy as a workaround.

I browsed the forEach documentation and went through possible solutions. One was to extend forEach and include a custom break function in it. But I decided against this for a few reasons. One, it would violate the rules (#3, to be exact). Over-extending a native function would bring more hurt than it would good. Second, Safari 2 has a problem with extending forEach, so it wasn’t a viable solution either.

But I had a hunch. What if I simulated a break by splicing off the remaining objects in the array, thereby terminating the loop entirely? I gave it a try:

var array = [1, 2, 0, 3, 4, 5];
array.forEach(function(item, i) {
  if (item === 0) {
    array.splice(i, array.length - i); // Simulated break
  } else {
    console.log(item);
  }
});

Success! The loop terminates, because there are no more objects to continue to. There’s just one problem: there are no more objects to continue to. It mutates the array, so it’s not reliable if you need to reuse the array. You’re limited to using it only once, or having to rebuild the array.

Ah, but what if you splice the array, and immediately concatenate it? Would it have the same effect and stop the array in its tracks?

var array = [1, 2, 0, 3, 4, 5];
array.forEach(function(item, i) {
  if (item === 0) {
    array = array.concat(array.splice(i, array.length - i)); // F-f-f-forEach breaker!
  } else {
    console.log(item);
  }
});

Double success! In this example, the array is spliced from the current index point, and all remaining objects are dropped off, ending the loop. The magic happens when we rejoin the array using concat, and reassign the newly constructed object to the array variable. The array is mutated back to its original form, and you’ve broken the forEach loop.

Still, it’s not as satisfyingly simple as a break, is it? Well, we can’t call a break, but we can get close. The next Flow revision will contain the exit Array extra, which will provide you with a keyword (or, as close enough a keyword as I could get) to break a forEach loop:

var array = [1, 2, 0, 3, 4, 5];
array.forEach(function(item, i) {
  if (item === 0) {
    array = array.exit(i);
  } else {
    console.log(item);
  }
});

Bug fix:

Flow will no longer choke with SWFObject.

Early this morning I received a report about Flow not playing nicely with SWFObject. After debugging, it turned out it was a case of doing too much.

SWFObject correctly cleans up after itself in IE by removing its generated code on unload. The conflict appears because Flow does the same with its code, going as far as eliminating all extended element properties.

So when SWFObject tried to removeChild, it returned null because Flow extends that property, and by the time SWFObject got to it, it was already wiped out.

Flow now merely restores an extended property back to its original implementation, rather than nullifying the property. This will fix the error.

Feature:

dispatchEvent is now implemented in Flow. You can use it to fire events on elements from another element. Confusing? Here’s an example:

var test = document.getById("test");
test.addEventListener("click", function() {
    // console.log(this.id);
}, false);
 
document.getById("dispatcher").addEventListener("click", function() {
    test.dispatchEvent("click");
}, false);

You can pass any event type and it will fire all events coupled with that type.

As usual, you can download the Flow framework at http://flowjs.com

It started with Dean Edwards and his release of the Base2 library. It scratched an itch that I’ve had for years: I wanted the ability to use the DOM API (Level 3) in all modern browsers. Base2 has since seen a second revision and is even more powerful than before. (Aside: Dean Edwards’ is a freaking genius.)

But I wanted more. I wanted a hybrid API that would allow me to use the standard API, but would also contain helper functions, shorthand notation, chainability, etc. So I got to work.

After eight months of development, trials, tears and tribulations I am pleased to announce the initial release of The Flow Framework.

Flow aims to fix and enhance the DOM Level 3 API. Flow extends API functionality to browsers that currently don’t support it. Additionaly, it adds powerful functionality on top for the best bang for your JavaScript buck.

A sample of the functions it implements cross-browser:

• getElementsByClassName / getElementsByAttribute
• addEventListener / removeEventListener (with DOMContentLoaded support)
• preventDefault / stopPropagation
• addClass / removeClass / replaceClass
• querySelector / querySelectorAll
• shorthand notation (getById, getByTag, getByClass, etc)

Here’s a snippet of what can be accomplished with Flow:

Find all: ul.checked li

With Flow Core

var uls = document.getElementsByClassName("checked").filter(function(e) {
  return e.nodeName.toLowerCase() == "ul";
});
var lis = [];
uls.forEach(function(ul) {
  ul.getElementsByTagName("li").forEach(function(li) {
    lis.push(li);
  });
});

With Flow Extend

var lis = document.getByClass("checked").filter(function(e) {
return e.elementName() == "ul";
}).getByTag("li");

With Flow Query

var lis = document.querySelectorAll("ul.checked li");

Want to open external links in new windows via JavaScript?
document.getByAttr("rel", "external").setAttribute("target", "_blank");

Want to return false on those pesky blank-anchor links?
document.getByAttr("href", "#").addEventListener("click", function(e) {
  e.preventDefault();
}, false);

There are more code samples, documentation, unit tests on the official site. Be sure to download a customized Flow build and try it out!

For those that want to take a gander at the code, you can check out the source on Google Code: http://code.google.com/p/flowjs/.

There’s already a website using Flow in the wild. South Park Studios was unveiled a couple of months ago, and it’s been chugging along since. Unfortunately I was under gag order at the time while the final details were being hammered down. Now I can officially state that it’s using Flow and lovin’ it.

Many, many thanks to Schematic for supporting the release of this library, and to the many Schematicans who freely contributed to the library.

Thanks are also in order to the great JavaScript programmers who’ve turned us all on our heads: John Resig, Dean Edwards, Robert Nyman, Tino Zijdel, Sergey Ilinsky and countless others.

What started as a simple itch to scratch has turned into a full-fledged iPhone application, used by true honest-to-goodness people. Really!

The feedback has been nothing short of spectacular. We’ve received tons of praise and we’ve listened to your feedback, sometimes pushing out updates within hours of suggestions. A gigantic thank you to everyone who pushed us to keep upping the ante.

An extra amount of thanks to Major League Baseball and Twitter, the entities responsible for providing us data. Without them Pickleview would not exist.

To commemorate this milestone, I’m happy to say that we’re releasing the Pickleview code under the Creative Commons Attribution-Noncommercial-Share Alike 3.0 License. You are free to learn from it, distribute and modify (as long as you share alike). View the source here. Thanks to the good folk at iPhoneWebDev for hosting our files. We’re hoping it becomes the repository for open-source iPhone web applications.

Lastly, stay tuned. We’ve got things in the works, gears are grinding, and overtime is being spent.

Over the weekend I attended iPhoneDevCamp, a gathering of web geeks from around the globe with one purpose: to create applications for iPhone.

I went into the event with little-to-no expectation of anything happening. It being my first BarCamp I didn’t know the atmosphere, how we would mingle, etc.

What happened that weekend was something I won’t forget for some time. It was a great feeling to walk through the Adobe Town Hall and see energy popping from 300 minds at once. You could feel the electricity as people discovered loopholes and solved riddles that had puzzled iPhone developers since its release.

My story was rather interesting. After a canceled flight and barely making the 6:00pm start time (United: Never Again), I was sticking with my usual schtick: talk to no one, avoid eye contact. Twenty minutes in, I suddenly realized the magnitude of the event and was determined to talk to someone– anyone.

It was then I spotted a couple of individuals at a corner table, mingling away. I took a chance, and introduced myself. Ryan and Seto were their names. A short while later, Estelle joined the small table, and we started brainstorming.

I’d been developing a small web app I dubbed LiveScore for a Dodgers’ fan forum that I run. It gave real-time updates of Dodger scores, as well as some vital stats of each game. On a whim I opened up the app and showed it to the group. The gang really took to it, and from that point brainstorming focused around LiveScore.

Minutes later, we had a prototype: A web app/mashup that would combine live game tracking with the ability to chat along with friends on Twitter.

And so, Pickleview was born.

In the span of 36 hours, we four furiously coded together the required bytes to get the app off the ground, and wrapped it around a native-looking UI. It was thrilling to say the least, if not completely overwhelming. I don’t believe I’ve ever coded so much in so short a time.

We had our small moment in the sun, making some top ten lists and being interviewed by the San Jose Mercury Press. But the real payoff was being able to release a very useful app for others to enjoy.

That, and comments that would make anyone jump for joy. Thanks again, Joe.

Since the camp, we’ve been working hard to improve our little app that could. We’ve added features such as play-by-play, visual cues on score, balls/strikes tracking, and lots and lots of bug fixes. I have to say I’m enjoying the ride. All for an app I’m proud to be a part of.

I should reiterate that neither I nor Ryan nor Seto nor Estelle had ever met each other before Friday. It was a great experience to be able to accomplish so much with virtual strangers. Pickleview, however, is quickly making us closer acquaintances.

New in this version:

• Faster, safer implementation of callback functions
• Now supports uploading files via Ajax(ish)

Check out the sample code for more.

Remote is a global, lightweight XHR/JSON function, designed to handle cross-browser remote scripting.

For XMLHttpRequests, it uses the native XHR object for browsers that support it. For IE versions 6 and below, it defaults to using XML Data Islands (when permitted). If all else fails, it reverts to using an ActiveXObject.

Remote supports JSON (Javascript Object Notation), as well as the JSON-RPC spec.

Remote has been successfully tested with the following browsers:

• Internet Explorer 5.5
• Internet Explorer 6
• Internet Explorer 7
• Firefox 2
• Camino 1.1
• Safari 1.3/2.0
• Opera 9

I’m pleased to offer Remote for download to anyone in need of a cross-browser XHR/JSON script. I am releasing the script according to the Creative Commons Attribution-Share Alike 3.0 License. You are free to use, distribute, and modify the script (as long as you share alike).

Feel free to take a look at the Remote API. And feel free to submit any bugs or questions you might have.