Tag Archives: ajax

Javascript Libraries Popularity

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JavaScript and Market Share?!

It’s kind of strange to speak about JavaScript libraries and market share, so lets called it “popularity”. Have you ever been interested on which is the most famous JS library.

I’d guess everybody has the answer in his head, right? jQuery is becoming for the JS community something like Google for the web or IE6 on the browser’s market in the beginning of the century. How odd?!

However here’s a short list of who’s first.

1. Robert Nyman’s poll:

Note: original poll page’s here.

Clear enough jQuery rocks. As I personally use jQuery I still think that its success is based on his easy to start nature. However lets see another result chart.

2. Chris Coyier from http://css-tricks.com is showing almost the same result:

Note: original poll can be found here.

3. Finally Polldaddy’s hosting a poll, where the results are even more interesting.

Polldaddy

Note: original source of the poll.

From these results I get more surprised not so much from the jQuery big advantage, but more from YUI. It’s a really very very powerful JavaScript library, perhaps misunderstood maybe because of it’s native complexity, don’t know?!

Storing JavaScript objects in html5 localStorage

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There is a rising new age of HTML5, which comes with very nice features as video tag and localStorage. What localStorage is? In fact we have been waiting for long time to have something that give us the power of storing more and more on the client side. That’s because the net is becoming larger and therefore heavy.

Imagine if you have the possibility to store large JSON returned from an AJAX call on the client. That’s now reality with the localStorage object in HTML5 and it can be accessed with something like this code:

localStorage.setItem(key, value);
alert(localStorage.getItem(key));

Can we store entire objects?

Yes there is a way extending a bit the logic of the code above. The localStorage in fact stores only strings, but what about arrays and objects. You can additionally use JSON global objects and its two methods – stringify and parse:

var a = JSON.stringify({name:'obj'});
alert(JSON.parse(a));

Do browsers support all that?

Of course … not! localStorage is supported by Firefox 3.5+, Chrome 2+, Safari 4+ and MSIE 8+. The solution is not to rely on browser version, but to check for object existence, and than to combine both techniques:

localStorage.setItem('a', JSON.stringify({ name : 'obj' }));
alert(JSON.parse(localStorage.getItem('a')));

JavaScript optimization. Lazy loading.

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Javascript files are too big!

Yes that’s the reality and when they become more and more bigger the web pages becomes to be irresponsible. The bitter reality is that you load any functionality that slows down the first user impression, but is needed only when you click on a button and so on. That’s a problem because you can load only that chunks you need in the beginning and than after a few seconds to load everything else. Some web applications have more than 100K of javascript which become really bad.

Separate logic

What you can do is to separate the logic into one or more files. Even when the user thinks everything is on the page and he can interact with the application and than to start to load the rest of the functionality.

That’s a pretty good technique. Nobody can start interacting on the 5th second of the load process. Usually the user looks at the interface starts to explore the app and after approximately the 10th second he start interacting with the page.

Lazy loading

There are various techniques of loading JavaScript on demand. So I wont cover it, but that pattern of loading it latter when needed is really powerful.

Manage JavaScript and CSS includes within Zend Framework application

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How to include JavaScript and CSS files?

In Zend Framework there is a very elegant way to include CSS and JavaScript. Because in one single view of any action you cannot include a JavaScript or CSS because they wont be executed from the browser, you can simply use a helper.

You can see the original source of how that’s done here. And in breve you can include a JS file like so:

<? $this->headScript()->appendFile('/media/js/global.js') ?>

but where the problem is?

As a very good PHP point of view, there is really that way to include JS into the application. But a PHP point of view is not a JavaScript point of view so this solution is not the best one.

As almost everybody knows JavaScript blocks other content until it’s loaded and executed from the server and nowadays the most popular way to include JS is just before the closing <body> tag.

That’s why the ZF solution is not optimal. What we actually need as both PHP and JavaScript developers is a most robust solution!

Speed up the JavaScript. It can change dramatically the user experience.

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JavaScript in a modern web application

If someone asks you what is the javascript in modern web developer, probably you should answer it’s almost the half of the traffic of your site and it’s almost everything when dealing with user experience.

Today’s big web apps are useless without it AJAX/JS part. Think about Facebook, Google products, Twitter, Yahoo!, Youtube.

Actually they made this a standart. The times when you used to use JavaScript as a helper language just to figure out how a drop down menu will work are far way in the past. Now JavaScript is everything in a rich web sites. With no JS they will be no rich at all! Then it comes the question how to improve sites with lots of javascript. Actually one of the main problems in the web now is that JavaScript is blocking content.

Blocked by the JavaScript

What that means at all is that until the browser receives and parses the JavaScript file/s it doesn’t process anything else, it even doesn’t load any other resources. Now you can imagine how big the problem is. When it comes to large files more than 100K the user experience will be very bad!

Optimize the web? What about optimizing JavaScript!

If the problem is so big as I described above why should we doubt about where to start with the optimization process? But of course with the JavaScript and the natural question that rises is how this can be optimized at all?

Three steps

Like me, many of you may heart of some techniques that improve javascript performance. Here are some I was able to select as important:

1. minify/compress

That’s rule number one. If everything that is a JavaScript file is processed once it arrives to the client than make it smaller and make it go faster trough the wire. Actually one technique to speed up things more is to concatenated all the files you have into one single big file. Although this will not spend you some space will reduce the HTTP requests and therefore speed up the loading process. Good tools that you can use to minify javascript files are the Yahoo’s YUI Compressor, that beside that compresses CSS and Google Closure Compiler. Both are extremely useful and by the last measurements the Google’s Compiler is even better, but it’s up to you to decide which one to pick up.

2 .write fast and smart code

You can minify everything that’s JavaScript and the code may remain slow. But why is that? That’s because the JavaScript is written in a bad way. You know there are many resources in the web describing what is a bad and what is a good practice when writing JS. Even more you can measure it by yourself if you’d like to use the Firebug’s profiler. That’s a good start to avoid bad practices.

3. improve loading – lazy loading

That’s a bit more complicated. If there’s a really big javascript file after compressing and concatenating all the JS functionality remains big. How to avoid that? Simply let’s the user to see the most important functionality and than load the entire app. Some good tutorials about lazy loading again can be found online. Don’t hesitate to search about.

Beside this really basic advices I’ll continue to write in my blog about specific techniques how to improve the JavaScript as this is one of the most interesting parts of web development by me.