:valid, :invalid, and :required CSS Pseudo Classes
Let's be honest, form validation with JavaScript can be a real bitch. On a real basic level, however, it's not that bad. HTML5 has jumped in to some extent, providing a few attributes to allow us to mark fields as required or only valid if matching a given regular expression. What some people don't know is that you can style elements base on their required, valid, or invalid values. Here's how!
The CSS
Each state is colon-separated from the element it's associated with:
/* basics */
input:required {
border: 1px solid blue;
}
input:valid {
border: 1px solid green;
}
input:invalid {
border: 1px solid red;
}
These pseudo classes are straight forward and useful. Here we're changing only borders, but you could use :before and :after to place text or an image next to each field, representing their state.
Being able to style elements based on invalid or valid information is something we've shimmed forever with JavaScript, but now we can do so (to some degree) with pure CSS!
![7 Essential JavaScript Functions]()
I remember the early days of JavaScript where you needed a simple function for just about everything because the browser vendors implemented features differently, and not just edge features, basic features, like addEventListener and attachEvent. Times have changed but there are still a few functions each developer should...
![I’m an Impostor]()
This is the hardest thing I've ever had to write, much less admit to myself. I've written resignation letters from jobs I've loved, I've ended relationships, I've failed at a host of tasks, and let myself down in my life. All of those feelings were very...
![CSS Fixed Position Background Image]()
Backgrounds have become an integral part of creating a web 2.0-esque website since gradients have become all the rage. If you think gradient backgrounds are too cliche, maybe a fixed position background would work for you? It does provide a neat inherent effect by...
![Create a Quick MooTools Slideshow with Preloading Images]()
I've been creating a lot of slideshow posts lately. Why, you ask? Because they help me get chicks. A quick formula for you:
The following code snippet will show you how to create a simple slideshow with MooTools; the script will also...
A small note:
:beforeand:afteronly works with elements that have content.inputs doesn’t, so these pseudo-elements won’t work.Amazing post, so in your example you are testing it with input text and email address is that all ?!
“now we can do so (to some degree) with pure CSS!”
could you please go into more detail about that degree? Browser support? Is this CSS3 only?
@Sumit – I can’t find any references on caniuse.com or anything similar. From my testing it works on: latest Chrome, latest Firefox, lateset Safari and IE10+. It doesn’t work on IE9 or below.
The :before and :after pseudo-elements elements interact with other boxes… as if they were real elements inserted just inside their associated element. More… http://www.corelangs.com/css/basics/pseudo.html CSS pseudo-elements
Eric
Bug in IE usign pseudo-elements
http://codepen.io/diegoleme/pen/cJyjF
A pseudo-class is similar to a class in HTML, but it’s not specified explicitly in the markup. Some pseudo-classes are dynamic — they’re applied as a result of user interaction with the document.
for full implementation of pseudo class to refer here:
http://www.mindstick.com/blog/711/CSS%20Pseudo%20Class