When to use the css element/class selector in javascript?

Question

I'm currently working on the codecademy course on building an interactive website and I stumbled upon an ambiguity concerning the use of the elemement/class selection of the css elements.

javascript:

var main = function() {

    $('.article').click(function() {
        $('.article').removeClass('current');
        $('.description').hide();
        $(this).addClass('current');
        $(this).children('.description').show();
    });

};

css:

.current .item {
  background: rgba(206,220,206,.9);
}

Why do I have to use the element selector 'current' instead of the class selector '.current' in line 4? Is there any rule behind it or just a specification of jquery?

YourFriend · Accepted Answer · 2015-02-23 11:33:59Z

10

Simply because the name of the class is current not .current, and in

$('.article').removeClass('current');

current is not any selector but just a classname which you want to remove, instead the selector is .article.

You are thinking that we are using element selector instead of class selector. But you are wrong. Do you see the word Class in removeClass and addClass ? It means you are passing class selector, not element selector as an argument.

Now you may ask why don't you see dot with current? Because classes are specified using dot. Actually we have already specified that we are passing Class Selector, as you can see word "Class" in removeClass and addClass .

edited Feb 23, 2015 at 11:33

YourFriend

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answered Feb 23, 2015 at 11:17

void

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2 Comments

Dennis Nedry Over a year ago

thanks a lot for your answer! so it's just because the method already expects a class - right?

void Over a year ago

Yes exactly, the removes a class (and it expects the parameter a class name). If it helped you please upvote and mark it as correct answer.

Milind Anantwar · Accepted Answer · 2015-02-23 11:18:19Z

1

as per docs addClass():

Adds the specified class(es) to each of the set of matched elements.

Hence, you need to pass the classname/names as parameter and not class selector built out of it.

answered Feb 23, 2015 at 11:18

Milind Anantwar

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Comments

Bergi · Accepted Answer · 2015-02-23 11:18:05Z

1

In addClass/removeClass you use a class name (like the one you'd specify in the class attribute of your html), not a DOM selector like in $().

answered Feb 23, 2015 at 11:18

Bergi

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Comments

oshell · Accepted Answer · 2015-02-23 11:18:19Z

1

The function name removeClass() implies you have to state a class name. Using a selector you have to specify either you want to select a class or an ID.

answered Feb 23, 2015 at 11:18

oshell

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Comments

James Hibbard · Accepted Answer · 2015-02-23 11:19:26Z

0

The addClass and removeClass methods accept one or more space-separated classes to be removed from the class attribute of each matched element. The name of the calss you want to add/remove is "current", not ".current"

http://api.jquery.com/removeclass/
http://api.jquery.com/addclass/

answered Feb 23, 2015 at 11:19

James Hibbard

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Comments

Vaibhav · Accepted Answer · 2015-02-23 11:20:56Z

0

In line 4, you are not using 'current' as a selector, it is a class name. Whenever you use some class name as a selector( for example in .find('.current'), $('.current') , closest('.current') etc) then only the rule of putting.for class name#` for id etc are used. And whenever you are checking some class exists( .hasClass()), adding and removing a class(addClass('current'), removeClass('current'),then you have to mention correct class name. I hope it helps.

answered Feb 23, 2015 at 11:20

Vaibhav

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