Elsewhere on the 'Net - Data Retrieval

Data Retrieval elsewhere on the 'Net.
Part of JavaScript.

10 January 2008

Cross-Site XMLHttpRequest

John Resig explains cross-site XMLHttp. The principle is simple: someone offering data may opt to add a header that says which other sites are allowed to download and play with the data.

A few months ago I mused about something like this, but I didn't post anything about it since I couldn't (and can't) judge the security consequences. Now the Firefox team says there aren't any (which seems to be implicit in them incorporating this feature in FF3), which is good enough for me.

Data Retrieval | Permalink

12 December 2007

Comet works, and it’s easier than you think

Simon starts evangelising Comet, a system for continuously pushing JavaScript to the client. Although the idea is not new (I remember an experiment by Scott Andrew somewhere in 2000/1), it seems to have been set up thoroughly now.

Let's see where it's headed.

Data Retrieval | Permalink

2 April 2007

The Ajax/Flash continuum

Jeremy on Ajax and Flash, and the continuum between web sites and web applications. When you're working on the application side, Flash becomes a serious option, while Ajax is generally harder to code and less accessible.

Data Retrieval, Flash, Theory | Permalink

20 March 2007

Flash vs. Ajax: It's time to expand your toolbox

Dan talks about Flash vs. Ajax, and takes Jonathan's presentation at SxSW as a starting point. Dan investigates the reasons he decided to quit Flash programming, and notices many of these reasons have meanwhile been solved.

Data Retrieval, Flash, Theory | Permalink

9 March 2007

JSON is not as safe as people think it is

As it says. Curious Firefox features may pose a threat to 'secure' JSON.

(Via Simon.)

Data Retrieval | Permalink

23 January 2007

Improving accessibility for today’s AJAX - To hack or not?

A call for screen reader users willing to test the recently published virtual buffer update trick (see under 20 January).

Accessibility, Data Retrieval, Screen readers, Tests | Permalink

20 January 2007

The story of XMLHTTP

How XMLHTTP came to be. By the inventor.

Which is the real explanation of where the name XMLHTTP comes from- the thing is mostly about HTTP and doesn't have any specific tie to XML other than that was the easiest excuse for shipping it so I needed to cram XML into the name (plus- XML was the hot technology at the time and it seemed like some good marketing for the component).

Interesting read all in all, especially because it shows once again that this sort of stuff isn't planned: you create something for your own reasons, but suddenly it takes on a life of its own.

(Via Nate.)

Data Retrieval, History | Permalink

Improving Ajax applications for JAWS users

About some interesting Jaws features. Summary:

Popular screen readers use a virtual buffer to allow users to interact with web content, whereby the virtual buffer provides a mechanism for screen reader users to interact with web content. This article uncovers undocumented behaviour in JAWS 7.1 and later, which allows web developers to build Ajax applications that update the virtual buffer without any interaction from the user.

Delves deeply into Jaws's bowels. Not for the fainthearted.

Accessibility, Data Retrieval, Screen readers | Permalink

12 January 2007

Why JSON isn’t just for JavaScript

So true: JSON can be used in any environment; it's not restricted to JavaScript.

However, there's an important social issue here, which is reflected in Dave Winer's post on JSON: people outside the front end community aren't (yet) used to it, so they will tend to underestimate it.

That problem will solve itself, although it might take a few more years.

Data Retrieval | Permalink

1 November 2006

The <module> Tag

Douglas Crockford proposes a modification to JavaScript's Same Source Policy in order to make cross-domain data retrieval possible.

Data Retrieval, HTML | Permalink

19 October 2006

Keep your JSON valid

It turns out that JSON requires you to use double quotes everywhere, even for your property names. JavaScript object literal notation does not require this; but it turns out JSON is a subset of the JS object literal.

I didn't know this; and as a consequence my book doesn't treat this rule. In fact, I have doubts about its practical necessity. A JavaScript object is a JavaScript object, whatever kind of quotes you use. OK, with the wrong quotes it isn't "JSON" any more, but all scripts will happily read and parse the objects, and do whatever they need to do.

Data Retrieval | Permalink

11 October 2006

Today’s AJAX and DHTML Best Practices

Excellent overview of recent thinking on Ajax and accessibility.

Accessibility, Data Retrieval | Permalink

Ajax loading screens

Stuart points out an important usability requirement of Ajax sites: no discernible load time.

There is no point in using Ajax if you have to pop up a “Loading” screen and wait ten seconds when a link is clicked.

Spot on.

Data Retrieval, Usability | Permalink

14 August 2006

JSON All The Way

Drew McLellan feels JSON is superior to XML. I'm not sure I agree, but it's useful to have a few major arguments concentrated in one entry.

Data Retrieval | Permalink

5 August 2006


JSON has been officially RFC'd.

Data Retrieval | Permalink

28 July 2006

Firefox 1.5, XmlHttpRequest, req.responseXML and document.domain

responseXML is not available when you use document.domain to allow pages from several subdomains to communicate.

Data Retrieval, Mozilla | Permalink

29 June 2006

How to Make Your AJAX Applications Accessible - 40 Tutorials and Articles

As it says. I read only a few of them, and wrote one of them.

Accessibility, Data Retrieval | Permalink

12 June 2006

Ajax Patterns

List of Ajax patterns; similar to what I myself am looking for in my QuirksBlog entries, but a bit more low-level.

Data Retrieval, Theory | Permalink

9 June 2006

An XMLHTTPRequest tip

A tip from the MSIE team: in IE 7, use the native XMLHttpRequest object, and not the ActiveX objects you need for IE 6 and lower.

Data Retrieval, IE | Permalink

25 May 2006

Making Ajax Work with Screen Readers

'We explain the fundamental issues; how to inform users of assistive technology that a change has taken place, and how they can interact with the content. To illustrate our findings, we summarise the behaviour of popular screen readers.'

Accessibility, Data Retrieval, Screen readers | Permalink

9 May 2006

Build Half a Product: Is Ajax accessible? At all?

Surprisingly, Joe's conclusion is 'Everybody could do everything. It just wasn’t all that convenient.'

Accessibility, Data Retrieval, Screen readers, Tests | Permalink

17 February 2006

The Real AJAX Upside

In which Tim Bray discusses the advantages of Ajax from a server side perspective.

Data Retrieval | Permalink

13 February 2006

Alternate Ajax Techniques, Part 1

On generating new script tags and downloading new scripts.

Data Retrieval | Permalink

26 January 2006

Developing Ajax Applications That Preserve Standard Browser Functionality

How to enable the Back button in Ajax applications.

Data Retrieval, Usability | Permalink

Preloading Data with Ajax and JSON

An interesting example of caching JSON requests. Just make the next request before the user actually commands it, and your application will appear to work smoother. Of course this is only possible in a linear situation.

Data Retrieval | Permalink

18 January 2006

AJAX: reducing latency with a CDN

A proposed measurement for network latency of AJAX applications. Interesting read.

Data Retrieval | Permalink

9 January 2006

Treating the HTTP Status code right

Some useful examples of using HTTP status code in AJAX calls.

Data Retrieval | Permalink

23 December 2005

JSON Benchmarking: Beating a Dead Horse

Dave Johnson did some benchmarks for W3C DOM, JSON and XSLT as Ajax response formats. His conclusion is that XSLT is by far the fastest method. I hope he gets around putting his test pages online soon, so that people can verify this conclusion.

Benchmarks, Data Retrieval | Permalink

17 December 2005

Yahoo! Developer Network - JavaScript Developer Center

With interesting information about AJAX and JSON in general, as well as the Yahoo APIs.

Data Retrieval | Permalink

16 December 2005

JSON and Yahoo!'s JavaScript APIs

Yahoo goes JSON. The JSON solution begins to become interesting. I didn't realize it can be used to ignore cross-domain security, but now that Simon spelled it out it's obvious.

Data Retrieval | Permalink

28 November 2005


Contains a few browser bugs that don't seem to be covered anywhere else.

Data Retrieval | Permalink

9 September 2005

Async Requests over an Unreliable Network

As it says. Required reading.

Data Retrieval | Permalink

AJAX Latency problems: myth or reality?

Jep Castelein gives a useful overview of latency problems in AJAX: how and when should you download data? Preload it? Load it only when the user requests it? Small chunks? Large chunks?

Data Retrieval, Linkdumps | Permalink

5 September 2005

What is “this”?

Problems with the this keyword in xmlhttp's readystatechange event. Turns out that Explorer considers it the window, Mozilla the event handler, and Opera the xmlhttp object.
Interesting bit of lore.

Data Retrieval | Permalink

28 July 2005

Best Practices: Implementing javascript for rich internet applications

Useful overview of basic best practices. Needs to be expanded enormously, but it's good that someone is making a start.

Data Retrieval | Permalink

22 July 2005

Ajax reconsidered

Some reasons why AJAX is more popular than DHTML was back in the nineties. Also a few caveats that apply when working with AJAX applications.

Data Retrieval | Permalink

14 July 2005

AJAX: Usable Interactivity with Remote Scripting

Excellent introduction to using XMLHTTPRequest by Cameron Adams.

Data Retrieval | Permalink

AJAX: Best practice for Asynchronous Javascript

A candidate AJAX best practice. I'd go for a simplified option 2: remember the node the data should be appended to and append it even when the user has clicked elsewhere.

Data Retrieval | Permalink

7 July 2005

Ajax Mistakes

Must-read about the usability of AJAX applications.

Data Retrieval, Usability | Permalink

This is the linklog of Peter-Paul Koch, mobile platform strategist, consultant, and trainer. You can also visit his QuirksBlog, or you can follow him on Twitter.

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