Exploring CSS3 Box-sizing
Let’s take a closer look at CSS3 box-sizing. Not too long ago, when you wanted to design a box on a webpage using a div element, you would typically set both the width and height to 100px. Additionally, you would add 10px of padding and 10px borders to the box.
However, this setup would cause browsers to increase the box’s size to 140px. The total width or height of the box would be 140px, which includes the original width or height (100px) plus twice the padding (2 x 10px) and twice the border thickness (2 x 10px).
But sometimes, I want my box to stay the same size no matter what padding or borders I add. It can be a real challenge when designing web page layouts.
That’s where the CSS3 box-sizing property comes in handy. It lets me control how the CSS box model works.
Becoming a box-sizing expert
With the box-sizing property, I have two options: content-box, which is the default setting and expands the box model as described before, and border-box. The second option ensures that the box shape stays the same size as I specified, including any padding and borders.
Let’s talk about a cool trick called border-box. Imagine you have a box that is set to be 100 pixels in both width and height. Now, let’s say you add 10 pixels of padding and borders. Normally, this would make the box larger, right? But with border-box, something magical happens. The box actually adjusts its content size so that the outer dimensions stay the same. In this case, the content size becomes 60 pixels, which means the box with padding and borders still looks 100 pixels big!
Browsers and Compatibility
The box-sizing property works well with modern browsers such as Firefox 3.6+, Safari 3, Opera 8.5+, and Internet Explorer 8 and newer. So, if most people visiting your website use these versions or newer, using this property can greatly improve the design of your layout.
box-sizing: border-box;
-moz-box-sizing: border-box; /* Firefox 1-3 */
-webkit-box-sizing: border-box; /* Safari */ >
By adding the above CSS snippet, you can ensure that the box-sizing rule applies to all elements on your site. This simplifies the management of your layout and makes sure that everything looks consistent across different components.
A Practical Example
Let’s see how we can use the box-sizing property to create a simple navigation bar. The bar will have five links, which we’ll structure using the following HTML code:
To make it look better, I’ll set the navigation bar to have a fixed width of 500px. Each link will be 100px wide. I’ll arrange the list items side by side and give each link a unique background color, so it stands out visually.
“`html
“`
Initially, our navigation looks like a regular one.
I have a little problem. When I try to add borders to the links on my navigation bar, something strange happens. Instead of just adding the borders, the links actually get wider. Each link goes from being 100 pixels wide to being 102 pixels wide. And to make matters worse, the total width of the navigation bar ends up being more than I wanted it to be. It ends up being more than 500 pixels wide. Can you believe it?
To fix this, I suggest using the box-sizing attribute. It ensures that the navigation’s size remains consistent, even when accounting for the thickness of its borders.
Now, if you’re interested in learning more about CSS, I’ve got some great resources for you:
– First, Tech Republic has a comprehensive guide on understanding the CSS Box Model.
– Next, there’s a detailed bug report on BugZilla about a box-sizing bug in Firefox.
– And finally, Paul Irish shares some insights on the advantages of using box-sizing.
These resources will help you expand your knowledge and delve deeper into the intricacies of CSS. Happy exploring!