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CSS CSS Layout Techniques Display Modes Block vs. Inline Elements

Ken Hibino
Ken Hibino
17,009 Points

Class or Id?

I have a very rudimentary question. When you are building a base layout for a webpage, why do people usually give a class rather than an id, when you only use that class one time. (For example, class="main-logo", instead of id="main-logo"). Isn't it more efficient to select ids than classes. Could someone please answer this very basic question?

2 Answers

Lin Lu
Lin Lu
29,171 Points

Class selector in CSS is used to select multiple elements in your HTML, they share the same class attribute. However, ID is unique, meaning you can select only one element at a time using an ID selector.

Ken Hibino
Ken Hibino
17,009 Points

So you use class="main-logo" because you want to use it in other part of the page?

or you may want to use it in other pages ;) !

Lin Lu
Lin Lu
29,171 Points

Yes it is possible to use the same class more than once in the same page. Another difference between class and ID is that an element can have several classes, but only one ID. For example:

<button class="btn btn-default" id="btn">Button</button>

In your case, you might want to apply other classes than "main-logo" to the same element.

Ken Hibino
Ken Hibino
17,009 Points

Thanks guys! It helped me clarify the difference between the two :)