Some tweetable #js1k demos
Posted by Howard Yeend in javascript on August 31, 2010
JS1k is consuming me at the moment. I saw this entry by strager and it inspired me to push for a tweetable (<=140 byte) demo based on his.
By dropping the save/restore and alpha blending features, I was able to come up with a few candidates which I think look fairly pretty.
Unlike my previous allRGB and rot13 entries, where I had a definite goal in mind, here I’m really just playing with parameters until something cool appears on the screen. Which is kinda neat, it recaptures that innocent experimental spirit which was what first attracted me to programming when I was a kid.
js1k: an allRGB entry in <1k of JavaScript
Posted by Howard Yeend in javascript on August 30, 2010
It’s contest season! The An Event Apart 10k JavaScript app contest has just ended (my entry got 2½/5), there’s a node.js contest, and the JS1k contest is ending on Sept 10th. JS1k is a much purer contest, disallowing any external libraries, while the 10k contest allowed things like jQuery and external web services. As Frederick Polgardy puts it, js1k is “An exercise in constraint, resulting in a kind of executable haiku”.
For js1k, I’ve entered a port of my PHP allRGB entry. The allRGB project is a great idea in itself – create an image which contains every possible colour in the RGB space exactly once. That’s 256*256*256 colours (=16777216), in a 4096×4096 image. Quite a challenge for PHP, and certainly not the kind of thing you’d attempt in JavaScript, right? ;D
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Writing a JavaScript app in 10k (#aea10k) – Part One
Posted by Howard Yeend in javascript, web on August 28, 2010
Two weeks ago I discovered the 10k JavaScript contest organised by An Event Apart. It challenged developers to “inspire the web with just 10K”. I knew I’d be cutting things fine with just 11 days left before the deadline (including 5 at work and 3 on holiday!) but I was desperate to enter an application.
You can play with the final entry right here – http://10k.aneventapart.com/entry/details/243 – voting closes today so please be generous with your votes and comments. I’ve literally just now come back from holiday so I haven’t had a chance to badger everyone to vote yet. Go and vote! ;)
The idea’s been kicking around my head for a while: Read the rest of this entry »
Some thoughts on JavaScript
Posted by Howard Yeend in Firefox, javascript on July 14, 2010
I don’t know about you, but I grew up doing image rollovers in JS and other groundbreaking “dhtml” stuff. Since then CSS has evolved, web standards and browsers have evolved, and things are much much nicer than before.
One thing that is starting to change is the way we fundamentally approach javascript. Not simply the recent popularity of libraries such as jQuery, allowing us to literally “change the way we write javascript”, but also there’s now much more awareness of the power that javascript has, and we’re doing more mission-critical stuff with JS. We’re moving from favouring simple procedural snippets of javascript that add twinkles to the page to fully object oriented JS applications, exporting great swathes of functionality away from the servers and onto the client.
This is a great thing. In fact it’s little short of a miracle; the servers are running faster and so are the clients! There seems to be no trade-off; by deeply integrating JavaScript into our web applications we’ve gained speed at both ends!
Not quite though.
Fast PHP array_unique for removing duplicates
Posted by Howard Yeend in PHP on June 21, 2010
PHP’s native dedupe function, array_unique, can be slow for large amount of input. Here I’m going to talk about a simple function that performs the same task but which runs a lot faster.
Often, people spout PHP optimisation advice that is incredibly misguided, so I want to make it clear up-front that you should be benchmarking your scripts using xdebug before you start optimising, and very often the real bottlenecks cannot be avoided by using “micro-optimization”. Here’s a nice PDF on Common Optimization Mistakes.
Now I’ve got that disclaimer out of the way, I believe it’s OK to talk about making a faster array_unique because it’s often used on large amounts of data – for example removing duplicate email addresses, and as such there are genuine use cases for a fast array_unique in PHP. Also our fast_unique function can be several seconds faster than array_unique so we’re not necessarily talking about micro-optimisation here; on 200k duplicate entries, array_unique takes nearly 5 seconds on my windows dev box, fast_unique takes <1 second on the same data. On 2 million entires the results are staggering – performance graphs are given below (but then, why are you doing that kind of work in PHP?).
The function looks like this:
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Caching in Javascript with Cachejs
Posted by Howard Yeend in javascript, web on May 18, 2010
Here’s a useful open-source (MIT license) javascript caching object I developed for my job at GG.com, the best horse racing site on the net.
(I am contractually obliged to say that every time I mention the URL. Not really though).
Like most web applications these days, we make fairly extensive use of Ajax, sending and receiving JSON data across the net on hover events and so on.
However, we’ve found that all those HTTP requests can slow down the user experience, and causes unnecessary extra load on our application servers, so we decided to employ a client-side Least Recently Used (LRU) caching object, so that we can reduce the number of HTTP requests, and increase the response speed for cachable queries. It employs lazy garbage collection, just like memcached does. In fact we see this as a kind of “memcache for javascript”, if that makes any sense at all.
- Get Cachejs now on Google Code. I’d love to see what you do with it ;0)
It depends upon no external libraries. Here’s a simple usage example:
XKCD Colour Survey – a 3D visualisation
Posted by Howard Yeend in javascript, machine learning on May 4, 2010
Randall Munroe (of XKCD) has been running a “name the colour” survey for the last few months and today released the data. The results are broken down by gender, and he makes some fascinating obvservations.
I’ve been working on a colour-related project on and off for about a year now, and part of that has involved creating visualisations of the RGB colour space – plotting red on the X axis, blue on Y, green on Z. So I thought it would be interesting to map XKCD’s 954 most common colour names in three dimensions – his charts are nice n’ all, but sexy javascript 3d is, well, sexier:
If you click that, you’ll be taken to the demo page, where you can interact with the cube. It’s a bit juddery, working entirely with divs and DOM manipulation, rather than canvas. Here’s a view from the side angle that shows off the “3d-ness” a bit more:
Of course, a canvas is really a better solution, so here’s a version that renders onto canvas, which is much much faster, but currently omits the names:
Fast PHP – effective optimisation and bottleneck detection
Posted by Howard Yeend in PHP, Productivity, web on April 18, 2010
PHP is not the fastest language on earth. That honour probably goes to machine code. But like many high-level languages, PHP provides some handy abstractions, like named variables, hashmaps (associative arrays), a C-like syntax, object oriented capabilities, loose typing and so on – we trade processing speed for development ease.
So it’s quite a common problem that people find their large PHP web applications running quite slowly.
Here are some frequently encountered bottlenecks found in web applications generally, and PHP specifically:
CSS Gradient Background – Cross Browser!
Posted by Howard Yeend in web on April 2, 2010
You read that right. This works in:
- Firefox >=3.6
- MSIE >=5.5 (!)
- Safari >=4
- Chrome
Oh Em Gee, I’ve got a CSS-applied Gradient.
How neat is this?
I mean really, this is super cool.
And it degrades gracefully in older browsers and Opera.
My boss Mike passed this little CSS gem to me, and now dear reader I pass it to you. It was orignally developed by FakeDarren, who posted a great little CSS button example. I find it useful for those times when designers get all fancy with gradiented backgrounds.
I’ve condensed Darren’s CSS down to these four lines plus comments, which will give you the lovely Green-to-Black CSS fade background you can see above.
.gradientV{ /* thanks to http://blog.fakedarren.com/2010/01/cross-browser-css-gradients/ */ /* fallback (Opera) */ background: #008800; /* Mozilla: */ background: -moz-linear-gradient(top, #00FF00, #000000); /* Chrome, Safari:*/ background: -webkit-gradient(linear, left top, left bottom, from(#00FF00), to(#000000)); /* MSIE */ filter: progid:DXImageTransform.Microsoft.Gradient( StartColorStr='#00FF00', EndColorStr='#000000', GradientType=0); }
And as you may have guessed by the ‘V’ in the class name, you can also do horizontal gradients – here are some more examples for left-right gradients, and we see what happens when we apply animations to a gradiented DIV.
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Super Useful Web Dev Tools
Posted by Howard Yeend in Firefox, PHP, Productivity, Programs, javascript on March 17, 2010
OMG, it’s been a whole month since my last update.
I have draft posts about all kinds of Good Stuff™, but none are quite publishable yet. So today I’m just going to point you at a few great resources I use all the time while doing my web development magic:
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