In , when Cascading Style Sheets were updated for the third time — creating CSS3 — designers and developers around the world rejoiced at what this new web standard made possible. CSS alone was a major overhaul to the way that the web worked. Instead of styling everything that went live online inside of HTML, making it next to impossible to update consistently or quickly later down the line without having to go through every single line of code, CSS stripped the styling and formatting from HTML completely and held it in its own container.
Hopefully this quick overview and basic guide helps you better understand the power, the leverage, in the capabilities that CSS3 brings to the table. Almost everything you see online today has been separated into at least two different digital documents — your HTML that makes up the content on your page, and your CSS that handles all of the aesthetics and the appearance of that same content. Think of CSS as the online language used to dictate the style and look of any one particular page or site online.
CSS can be used to position pieces of content, to establish background images or colors, to dictate the size, style, and font used, as well as a whole host of other aesthetic details that are so important to making our web experience as beautiful as it is today.
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The original CSS language represented a major leap forward in web design, and the second version of CSS brought forward a nether specification that helped give a lot more control to designers and developers. Now, let's move our display: contents styles into a feature query. Normally in this kind of progressive enhancement scenario we'd use the query to add the new styles, but it would also have to disable some of the original styles necessary for the fallback layout. However you might decide that because support for feature queries is pretty good if you ignore IE you actually want to use the feature query not operator.
It works just like you'd expect, so we can re-apply our original flex property to the list-items when display: contents is not supported:. Inside the not query we can add some styles so that the. You can already see the potential of feature queries, but the really cool thing is that you can combine expressions using the three available operators: and , or and not.
Perhaps we could also check for display: flex support and then add a float-based fallback. We're not going to do that here, but if we were we'd first modify the two feature queries like so:. Now we have a beautiful newsfeed in place, let's add a little chat box that is fixed to the bottom right of the screen. We'll need a list of messages and a text field for the user to enter their message. Hopefully now you'll have a little chat box with a scrollable list of messages sitting on top of your newsfeed. But have you noticed what happens when you scroll inside a nested area and you reach the end of its scrollable range?
Try it. Scroll all the way to the end of the messages and you'll see the page itself will start scrolling instead. This is called scroll chaining. It's not a big deal in our example but in some cases it might be. We've had to work around this feature before when creating scrollable areas inside modals or context menus. Say hello to overscroll-behavior.
CSS vs CSS3
There are three possible values:. We can use the shorthand overscroll-behavior or we can target a specific direction with overscroll-behavior-x or -y. Let's add it to our. This property is also pretty handy if you wanted to implement a pull-to-refresh feature in your PWA, say to refresh the newsfeed. Some browsers, such as Chrome for Android, automatically add their own and until now there has been no easy way to disable it without using JS to cancel events using performance-impacting non-passive handlers. At the moment the chat box takes up quite a bit of space, which unless we're interacting with it is a bit distracting.
HTML was originally created for hyper- text documents, with perhaps a few images, not rich media pages with audio and video.
01. Set up the HTML for the newsfeed
But some people seem unconvinced by this fact. Why not just do that? It's easier!
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There are a number of reasons to prefer HTML5, and to avoid using any of the deprecated features. Some are practical, while others are more philosophical. Some are altruistic, while others are selfish. You probably already know how to create HTML5 documents.
The basics of the language are the same. There's a just a few things that are good to keep in mind.
If you click on the links to the individual pages, you can learn more about why each feature was deprecated and how to accomplish similar effects using modern, standard features of HTML5 and CSS. If you research the deprecated tags, you can learn more about why each feature was deprecated and how to accomplish similar effects using modern, standard features of HTML5 and CSS. You don't have to memorize the list, though. All you really have to remember is that if you want to affect the way something looks on a page, you probably shouldn't attempt to do what you want with HTML. Nearly all of the HTML features that affected style or design have been deprecated, and the few that are left are only recommended in particular cases.
My Top Five Favorite Features of CSS3
Sometimes, if you don't know that something is available, you don't know to look for it. Many of the deprecated features were used to achieve design and styling effects. These are now properly the domain of CSS. If you want to be a modern web front-end developer, you'll spend some time getting good at using CSS.
3 Advanced CSS3 Techniques You Should Learn
That looks like:. These include:. The image itself is an attribute of the tag , not the content. Finally, you should make it a habit to validate your HTML documents against the specification. This means using an automated tool to check whether the markup adheres to the standard or not.