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2 Answers
jcorum
71,830 PointsYou can have only element with the same id in a page. You can have as many elements as you want with the same class. Or to put it another way, id values have to be unique. So if you have:
<p id="first">...</p>
You can't have another:
<h1 id="first">...</h1> //first cannot be re-used
But you can do this:
<li class="new">...
<li class="new">... //new can be re-used
<li class="new">...
<li class="new">...
<li class="new">...
<li class="new">...
<li class="new">...
So use id when the element will be the only one with that value, class otherwise.
Jennifer Nordell
Treehouse TeacherAn id is a unique identifier for an element. Take the id of "main-paragraph". You may not have more than one element on a given page with that particular id. However, a class can be used for multiple elements. For example you could have all paragraphs on your page use the class "generic-paragraph" and then target just one of them with the id of "main-paragraph". IDs are used when we want to specifically target one specific element. Hope that makes sense!