Shawn Bediako, associate professor of psychology, will speak at the 4th Annual Roland B. Scott Memorial Symposium. The topic of the symposium is “Pain in Sickle Cell Disease: Pain: Myths, Facts, and Stigma.”
The symposium will take place on May 7 at the Howard University Hospital. For more information, see the flyer below.
When creating JavaScript functions, we give names to each one of the arguments that our function takes. But what if you want a function to take more than one argument? Learn more about variable arguments in JavaScript with Jim, resident Treehouse JavaScript expert, in this Treehouse Quick Tip!
The post How to Create JavaScript Functions with Variable Arguments | Treehouse Quick Tip appeared first on Treehouse Blog.
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If you plan to use CSS on a regular basis you need to develop an understanding of what specificity is and how it is applied.
Other than floats and positions, specificity may be one of the hardest things to get used to, let alone master. The selectors you use in your CSS all have different weights and those are controlled by specificity. That’s why sometimes, when you apply a rule to an element, it isn’t reflected in your design.
If you’ve ever relied on the dreaded !important keyword to hack your CSS, then this article is for you.
To get your foundations solid, you need know how the browser actually reads CSS and how rules are overridden.
Firstly the browser will read a stylesheet from top to bottom meaning that with this code:
/*Line 10*/
ul li a {
color: red;
}
/*Line 90*/
ul li a {
color: blue;
}
The rule you specified at line 10 will get overridden and that anchor tag will be blue because the browser will consider rules further down your CSS to hold a greater priority.
This also works with the actual order you import your css files , for example:
<link href='css/style.css' rel='stylesheet'>
<link href='css/custom.css' rel='stylesheet'>
Since you placed the custom.css after the the style.css anything you write in the style.css (discounting for now, the weight of selectors ) will get overridden and substituted for what is in the custom.css, this technique is often used by theme creators to give the user some room to add their own styles without changing the main file. (Note however that custom.css doesn’t replace style.css entirely, only those rules that are specifically overridden will be replaced.)
Everything above only applies if you are using the same weight on every selector. If you’re specifying IDs, classes or stacking elements then you’re giving them weight, and that is specificity.
There are four categories that define the specificity level of a selector: inline styles (these ones are sometimes used by javascript), ID’s, Classes and elements. How to measure specificity? Specificity is measured in points, with the highest points value being applied.
Knowing this, if you use a selector like so:
#content .sidebar .module li a
Its total weight is 122 points ( 100 + 10 + 10 + 1 +1 ), which is an ID, two classes and two elements.
ul li a {
color: red;
}
This selector will hold a weight of 3 , which means that just by adding a class somewhere else, you can override it.
.content #sidebar {
width: 30%;
}
This selector has a weight of 110 points mainly because of the ID that adds 100 points of the 110 total.
.post p:first-letter {
font-size: 16px;
}
This selector has a weight of 12 points ,since the pseudo-element :first-letter only weighs 1 point and so does the p tag.
p {
font-family: Helvetica, arial, sans-serif;
}
This selector only weighs 1 point , this type of selector should be used at the top of the page when you marking the basic styles that later on may be overridden for specific areas.
Always bear in mind that to override an ID selector you have to write 256 classes for the same element , like so:
#title {
font-weight: bold;
}
.home .page .content .main .posts .post .post-content .headline-area .wrapper /* ... etc. ... */ .title {
font-weight: normal;
}
Only this way will the second selector beat the one using the ID.
Specificity isn’t a flashy aspect of CSS, but in my opinion it’s the area most overlooked. Getting your specificity right not only helps you avoid bugs, but it will speed up both your development and your final site.
Do you overuse IDs when writing CSS? Do you ever fall back on !important? Let us know in the comments.
Featured image/thumbnail, precision image via Shutterstock.
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The Codecademy Fellowship gives curious college students the chance to spend one year as professional software engineers working at a startup driven to change how people learn.
This spring we've had the pleasure of having Bob & Louis with us. Learn what they have to say about the experience below!
Why were you interested in becoming a Codecademy Fellow?
Bob: It seemed like an incredible opportunity to work with a very talented team working on a great mission.
Louis: Gaining some practical industry experience that would apply some of the things I learned in school seemed like a great next step to shape my career.
What projects are you working on at Codecademy?
Louis: I am working on the interactive evaluation environment for languages like Python, Ruby and recently released PHP.
Bob: I've spent most of my time here building the new Learning Interface.
How has the fellowship met your expectations?
Louis: They have been more than met. My expectations were to work with smart and driven people on problems that challenged me and gave me the opportunity to learn.
Bob: Definitely. It's an incredible learning experience to ship code everyday at a fast paced startup like Codecademy.
What is the best part about living in New York?
Bob: The energy of the city really is undeniable. There's always something going on, new things to experience and learn.
Louis: It's been exciting to be part of the diverse and growing tech community in New York.
Any advice for future fellows?
Louis: Think about yourself and your education critically - what are you good at, where do you lack experience? The fellowship is an opportunity to learn things that you couldn’t learn in a classroom or internship.
Bob: Be very specific with your application. Show us your personality, emphasize what makes you unique.
A modified version of Android puts social networking, and Facebook, at the heart of a device.
MIT Technology Review editor Rachel Metz live-blogged Facebook’s announcement from its headquarters in Menlo Park, California. Read her blow-by-blow account of the event below.
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