Nuno Silva

Getting an html element Attribute

To do this i use mootools, a very fast and handy JavaScript framework.

Imagine that you got an element as following:

<img id="image" src="..." aaa="true" />

To get the value attribute “aaa” using mootools you only need to do the following:

$("image").getAttribute("aaa");

This solution will work in all browsers.

Divs instead of tables

One of the complicated things when we are doing a design is to doing it only using divs and not tables. Some of us always use tables. And why? because it’s simple? Maybe using div’s is not so dificult after all.

First, there are several reasons to use a div layout instead of a table based layout:

• Flexibility: The main reason not to use tables in the main layout of your website is, in my opinion, flexibility. Has you can see in csszengarden, using divs to divide the content, turns the page layout into a flexible layout where you can make almost everything you want without change any html. If you want change the style of your page, you change the css. This is the way it should be made.
• Separation of Concepts: Using a table based layout you are mixing two concepts: Style and Content. Why? Because using a table based layout you only need to write some xhtml (has you will see below).
• Accessibility: Div layouts are more accessibility friendly.
• SEO Optimization: A Div layout is more optimized for search engines crawls.
• Bandwidth: using divs saves bandwidth because you need less xhtml to reach your objective.

I will take has example webgames.zi-yu.com, a website whose design is integrally constituted by divs but, in it’s original form, it was made using a table.

Let´s start with the layout of the page:

As we can see in the image above, there are 4 main areas, each one divided in subareas:

• A: the main title
• B: the left menu
• C: the main content
• D: the footer

Using tables this layout would be very simple to make:

	<table>
		<tr>
			<td rowspan="2">A1</td>
			<td colspan="2">A2</td>
		</tr>
		<tr>
			<td colspan="2">A3</td>
		</tr>
		<tr>
			<td rowspan="2">B1</td>
			<td colspan="2">C1</td>
		</tr>
		<tr>
			<td>C2</td>
			<td>C3</td>
		</tr>
		<tr>
			<td colspan="3">D1</td>
		</tr>
	</table>

With div’s the layout would be even simpler (and more easy to read - in my opinion, semantically correct). Let’s start by the beginning. We have 4 different areas, so we will have 4 different divs:

<div id="allContent">
	<div id="topMenu"></div>
	<div id="leftMenu"></div>
	<div id="mainContent"></div>
	<div id="footer"></div>
</div>

Now that we have the sections defined, let’s take care of the sub sections:

<div id="allContent">
	<div id="topMenu">
		<div id="logo"></div>
		<div id="topMenuUp"></div>
		<div id="topMenuDown"></div>
	</div>
	<div id="leftMenu"></div>
	<div id="mainContent">
		<div id="mainMenu"></div>
		<div id="mainContentLeft"></div>
		<div id="mainContentRight"></div>
	</div>
	<div id="footer"></div>
</div>

At this point all the sections of the page are defined. We only need to apply the css style to adjust it’s position and size. In this style (and in all the styles i make) i always consider a resolution of 1024×768. For this resolution, the maximum size i use is 1000, because of the vertical scroll of the browser. Normally this scroll is hidden but when it appears, the size of the layout is reduced and the horizontal scroll appears (thing that we don’t want).

So, considering the width of the layout 1000 pixels, let’s start with the logo:

#logo {
	width:252px;
	height:110px;
	float:left;
}

#topMenuUp {
	height:20px;
	border:0px;
}

#topMenuDown {
	height:90px;
	padding-left:0px;
	text-align:center;
	border-bottom:solid 1px black;
}

What the css above will do? Normally the 2 divs are positioned by default one below the other. So we will maintain that behavior for the div’s with the id topMenuUp and topMenuDown (only the height of them will be adjusted). Regarding the div with the id logo, we need to align it to the left, so we use float:left to obtain that result.

Next, the main content and the left menu. Generally i use the following stategy: if i have several containers in the same level, i separate them inside larger divs. So, i separated the leftMenu (area B of the picture above) and the div’s in the area C. The div’s in the area C i putted them inside a larger div in order to aligned them all at the same time into the right of the leftMenu div:

#leftMenu {
	width:252px;
	float:left;
	display:block;
}

#mainContent {
	width:745px;
	float:right;
	display:block;
}

Regarding the different sections inside the div mainContent, there is a top section (area C1), that will fill mainContent top, and two other div (areas C2 and C3) that will fill the rest of the div.

So regarding the div mainMenu (area C1), we will apply the following style:

#mainMenu {
	height:48px;
	padding:0;
	margin:0;
	clear:both;
}

The clear:both style is very important. It allows the div mainMenu not to have any content at it’s left or at it’s right. So, if other div (like the ones below) have a float style applied to it, that div will appear below mainMenu div.

Because the div mainMenu has the clear:both applied, the divs mainContentLeft and mainContentRight can be aligned with floats without a problem:

#mainContentLeft {
	float:left;
	width:584px;
}

#mainContentRight {
	float:right;
	width:160px;
}

Finally the footer. To this div i’ll just apply a clear:both style just to guaranty that no other div will overlap it:

#footer {
	height:48px;
	clear:both;
}

And that’s it, a layout that, at first sight, would be difficult to be made with divs, but, with simple css, it becomes very simple.

In conclusion, using divs, floats, clears and widths you can make almost any layout you want.

Wrapp a div around other div’s with float

Today i discovered something interesting with div’s.

Imagine that you have the following code:

<div id='mainDiv'>
   <div style='float:left'>Div #1</div>
   <div style='float:right'>Div #2</div>
</div>

And you wanted that the div named “mainDiv” to have a background color. Well in IE7 everything works fine with the xhtml code

above. But in FireFox the “mainDiv” there is an unusual behaviour.

Below is a image that ilustrates what you get in Firefox (on the left) and what you get using IE7 (on the right) with the xhtml code above:

Notice that the main div, in IE7, warps all content, but in Firefox the div remains with a minimum height.

Io solve the problem you could try (has i did) to put a height in the “mainDiv”. Although it worked (for the content that i

had inside the Div), you never know what the the height of the mainDiv is going to be.

The correct solution for the problem must be one that adapts the height the mainDiv to the maximum height of it’s content.

The solution is simple:

<div id='mainDiv'>
   <div style='float:left'>Div #1</div>
   <div style='float:right'>Div #2</div>
   <div style='clear:both'></div>
</div>

Adding the empty div with the style property “clear” set to “both” makes the mainDiv’s height extend to the full height of

it’s childs, making the xhtml generic for all browsers.

(UPDATE)
Due to the several solutions in the comments i will comment there here one by one.

Alternate Solution 1: the clearFix : thank to Joao A.

The solution in in fact very elegant and we only need to add something to your style sheet. The solution objective is to add

the pseudo element :after into that

“mainDiv”:

#mainDiv:after {
	content: ".";
	line-height: 0;
	height: 0;
	visibility: hidden;
	display: block;
	clear: both;
}

The pseudo element objective is to add some content after the element “mainDiv”. So the soluction passes by adding the

content “.”, removing the height of the content, hide that content and finnally clear both side of the div. in fact we are

doing the same has the original soluction without adding the extra div to the markup.

Alternate Solution 2: adding the float:left style to the “mainDiv” element : thanks to Vítor Pires.

This solution is actually very simple:

The solution is simple:

<div id='mainDiv' style='float:left' >
   <div style='float:left'>Div #1</div>
   <div style='float:right'>Div #2</div>
   <div style='clear:both'></div>
</div>

Alternate Solution 3: adding the overflow style to the “mainDiv” element : thanks to Jeff and href=’http://btm.anfo.pl/’ target=’_blank’>BTM.

very simple just like the previous one. Add the overflow style property with the value ‘hidden’ or ‘auto’.

The solution is simple:

<div id='mainDiv' style='overflow:hidden;' >
   <div style='float:left'>Div #1</div>
   <div style='float:right'>Div #2</div>
   <div style='clear:both'></div>
</div>

The only difference bettween the usage of overflow:hidden and overflow:auto is just that if you have a fixed height in the mainDiv, with overflow:hidden, the content will the content that surpasses the size of the div will be hidden, but with overflow:auto a sroll will appear.

The Solution 2 and the solution 3 are actually very good (and simple) to use in specific situation. if you want the content of the mainDiv to appear below it, than use solution 3 (or 1). Otherside, if you want the content to appear side by side with the div, use the float property in the main element.

Bird Zone

My friend Tiago finally released his website about birds.

It has a Portuguese and an English version (I think the english version is still under construction…). It needs some content but i think it’ a good start.

You can check it at aves.zi-yu.com (I must change this name… is not international… )

PS: Isn’t the banner Cool? ( I made it :D! )

Dam Internet Explorer

Today morning i noticed that my blog skin was totally upside down. No, i didn’t been attacked by an hacker.

In fact, the skin i am using wasn’t prepared for internet explorer. Because i normally use Firefox, i didn’t noticed.

So with a little bit off patience i opened the css file an tried to find the styles that needed to be changed. When i found them, i had to apply an css hack to work in both IE and Firefox.

The hack is simple. If you have the style:

.style{

margin:0;

}

and, in it’s context, works well in Firefox but not in Internet Explorer (or vice versa - this normally isn’t the case) we change the .style into the value that works good in internet explorer and create the a new style so it continues to work in Firefox:

/* Internet explorer applies this*/
.style{
margin:10px;
}
/* Firefox applies this*/
html>body .style {
margin:0;
}

If you have more styles, you can leave them in the original .style because firefox will apply them as well. You only need to override the styles that are changed.