When to use parentheses

Question

In the section 'More Pseudo-classes' when using the 'not' selector, the example is
css
input:not([type="submit"]) {
      border:2px solid #000;
      color: #fff;
}

and I took the parentheses away and it didn't work. 
But for the challenge using the 'checked' selector, I used
css
:checked[type="radio"] + label {
xxxxxxxxxxxxxxxxxxx
}

At first I wrote in parentheses around like :checked([type="radio"]) + label and it didn't work. 
I was wondering why one of these uses parentheses and the other one does not? What are the rules to using them?

Stone Preston · Accepted Answer

the not uses parenthesis because :not(X), is a functional notation taking a simple selector X as an argument.
So, because it is functional notation it must have parentheses. the checked selector does not use functional notation therefore it does not have parentheses. 
A  similar functional notation pseudo class selector is :nth-child() 
Source: https://developer.mozilla.org/en-US/docs/Web/CSS/:not

Rita Dunne · Answer

wow thanks so much! Both of those posts are incredibly helpful!

James Barnett · Answer

Here's a list of 30 CSS selectors you should know (http://net.tutsplus.com/tutorials/html-css-techniques/the-30-css-selectors-you-must-memorize/)
You only use parentheses for of-type & not selectors.

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Rita Dunne

Rita Dunne

When to use parentheses

3 Answers

Stone Preston

Stone Preston

James Barnett

James Barnett

Rita Dunne

Rita Dunne