Tag Archives: Software engineering

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!

Firebug’s console.profile vs console.time

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Firebug’s console.time!

This post is directly related to the previous post where I explain how to use the Firebug’s console object and in that case its time method. That is really powerful and gives the opportunity to track the performance of a sample JavaScript chunk of code. What it does not do is to give you a more detailed profile of that particular JS code.

That’s because the console’s profile method works on functions and if you’d like to profile a loop it will give you there’s nothing to be profiled. One workaround to that is to use closures.

JavaScript closures

A JavaScript closure is to make an anonymous function and to put the code in it, like so:

(function() {
 for (var i = 100000; i--; ) {
  var a = new Array();
 }
})();

Firebug’s console.profile()

That code can be than wrapped with both console.profile() and console.profileEnd() in something like:

console.profile('my profile');
(function() {
 for ( var i = 100000; i--; ) {
  var a  = new Array();
 }
})();
console.profileEnd('my profile');

That will give a more precise measurement like that one shown on the picture bellow:

firebug console.profile

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.

Optimizing CSS. Five simple steps!

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In the spirit of the optimization wave this post is about CSS optimization. There are some simple rules that you can apply. I’m pretty sure most of us have already been familiar with that list, but you never know.

1. Minify

As the JavaScript the CSS also can be minified. This only strips every character that makes the traffic bigger. As you know a well constructed and pretty looking CSS file consists of many new lines, tabs and spaces. Almost every software minifies the CSS by simply removing them. Some of the programs go even further with replacements of different parts of the code considered to be not efficient.

2. Use effective selectors

Some CSS selectors aren’t really efficient. Imagine something like: body div a just to describe only one specific link. That’s really bad. Better practice is to replace that line with something like a.my-class and to replace the a tag into the DOM with that class name. That will be far more effective. Actually if you’re wondering how to find such bad selectors, there’s a tool by Google called Page Speed that’s a Firebug’s plugin and can extract a list of all bad selectors.

3. Inheritance

CSS is really powerful when dealing with inheritance. That’s something that is not some clear but however really powerful. This technique is in the basics of the next rule.

4. Sprites

I’ve written already about CSS sprites. This is nothing new, but be careful when making a new site’s layout. CSS sprites spend you HTTP request and that’s rule number one according to Steve Souders’ list of optimization.

5. Separate logic

Sometimes developers put the site logic in only one file that become to large. Be aware of that. This is hard to maintain and you load things that you don’t need.

That’s a really short list of what you can do with CSS to speed the site up. I hope that can help someone when dealing with cascading style sheets.

Cool tutorial about Zend_Paginator

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Every part of Zend Framework is indeed very profesional and useful. But as it happens often some modules are less used than others. Don’t know why but my feeling is that Zend_Paginator, a wonderful tool for pagination is really misunderstood. And in fact it does one of the most common web development tasks. It builds the abstraction for a component that everybody uses in a web project – pagination.

It make sense if there where more tutorials like the following one describing its usage! Many thanks to Joey Rivera for a great tutorial about Zend_Paginator.

Even more this tutorials goes behind the pure usage of the paginator but it helps you understand the integration with one of the most used web apps today – Twitter and another Zend Framework component – Zend_Cache.

joey rivera blog