Category Archives: micro tutorial

JavaScript Snippets: IF Statements Optimization

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A “Typical Installation” …

As most of the desktop software gives us opportunity to choose from typical or custom installations, let me write what’s a typical IF conditional statement in JavaScript and … every other programing language.

if ( thisIsTrue ) {
    printMe("some message");
}

A “Custom Installation” …

The first thing you can improve from the code above is removing the brackets.

if ( thisIsTrue )
    printMe("someMessage");

Because in JavaScript everything’s on the client – every symbol matters. What if we remove as much as we can!

thisIsTrue && printMe("someMessage");

Change the Viewport, be Ready for the iPhone!

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Sites for mobile

Have you ever noticed that once you start designing a site for mobile, as iPhone and Nexus One from Google are, the site is looking really ugly! These two devices in particular, as may other using Opera Mini for instance, scale the site, because only than you can view the entire layout and than zoom to a particular part of the page.

This is nice because news sites as cnn.com or lemonde.fr are full of text & image information and once zoomed in they fit the screen – very nice feature of the browsers. However if you’d like to design a site for mobile the bad part comes here. Yeah you know how to detect the browser, that was a topic of one of my previous posts, but even than you fully functional, but less decorated site is scaled again and looks more ugly than the full version of the site.

Twitter for mobile

How to make a site visible in mobile …

Look at the http://mobile.twitter.com – the problem is that if you open this link with a normal browser, not from mobile, you’ll get redirected to the twitter.com and you cannot see the difference.

You can see how it’s made on …

The digg’s mobile version. Look at http://m.digg.com. This time you can see the different approach just by looking at the source code. Pay attention to meta tag in the head – it simply says – “don’t scale”. Nice thing to notice!

Don’t scale my site anymore:

<html>
 <head>
  <meta name="viewport" content="width=320; initial-scale=1.0; maximum-scale=1.0; user-scalable=0;"/>
 </head>
...
</html>

What make JavaScript closures work?

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Closures again

Most of the JavaScript developer don’t even know what a JS closure is and that’s why Crockfrod is so angry. Yes, it’s true, most of the “developers” just copy and paste the code without even know how it works. OK, just in breve the closure is an anonymous function, which thus helps you define a pseudo namespace, as you may know that in a function everything is visible inside it and only there.

function myFunc() {
    var a = 10;
}

The code above makes the variable a to be visible only inside the function. But as you know there must be a function call to make “all this code work”.

myFunc();

However you can make an anonymous function – or a closure, where the function is with no name and is called once the code has been processed. The right syntax is like so:

(function() { var a = 10; })();

Why and how?

The question is: why and how that works? Why this syntax is correct?

Hint

A tiny hint is that you can make the following line working:

var myFunc = function(){ var a = 10; }();

Pay attention to this syntax and the assignment is what makes all this working.

CSS right to left direction & floating elements

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direction:rtl

When developing a website for Arabic one of the most common questions is how to get it work with a reverse direction. Actually there is the CSS property direction:

.my-class {
    direction:rtl;
}

which makes the page right aligned.

Floating elements …

However sometimes there are elements on the page which are absolutely positioned and the direction property doesn’t do the job. The solution is something like combining the two settings. Both direction and float. So something like:

.my-class {
    float:left;
}

becomes something like:

.my-class {
    float:right;
    direction:rtl;
}

and of course if you’ve something like margin-left it should become margin-right!

JavaScript inheritance example

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JavaScript and inheritance

Almost for everybody the JavaScript way of implementing inheritance is odd. For a typical programmer it should look more C or Java like, but is not. However to give you a breve example, I’d like to make two objects, and to make the second one to inherit from the first. Thus I’d like to show how neither parent or child objects interact once they have been instanciated.

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	var parent = function() {};
	parent.prototype = {
		name : 'parent',
		m : 1,
		a : function() {
			console.log(this.name + ': ' + this.m);
		},
		setM : function( value ) {
			this.m = value;
		}
	};
 
	var child = function() {};
	child.prototype = new parent;
	child.prototype.name = 'child';
 
	var parentObj = new parent();
	var childObj = new child();
 
	parentObj.a();
	parentObj.setM(12);
 
	childObj.a();
	childObj.setM(3);
 
	parentObj.a();
	childObj.a();

However this describes the ability to make complex JavaScript inheritance patterns. The complete source’s here.