如何选择必须具有多个CSS类的元素？

Question

I have an element that has two classes at all times:

<p class="general_description laptop">
<p class="images laptop">
<p class="specs laptop">

One class describes the item ( laptop ) and the other ( general_description, images, specs ) describes the state that the page needs to be in to present one of three types of information about the item.

How can I show or hide the <p> element only if both classes in my selector are present?

For example, if I only want to show the <p> element that corresponds to both the specs and laptop classes, I have tried doing this but it does not work:

$(".specs .laptop").show();

Answer 1

$(".specs.laptop").show();

OR

you could use the is() function in jquery. it takes a selector and tells you if the element conforms to it:

$(".specs").is(".laptop"); //returns true if the element has the laptop class

Answer 2

IIRC，它是：

$(".specs").filter(".laptop").show()

Answer 3

Get rid of the space between the class names.

$(".specs.laptop").show();

Reference: jQuery