Can't we create atrtribute self in HTML ?

Question

Can't we create atrtribute self in HTML ?

I found some code to make slider with pure css and html, I found an attribute name code that I never found before, the tag is (slide and annot).

dan yang membuat aku pusing lagi, attribute name ini bisa kita gunakan pada Pseudo-classes.

/-----start-HTML----/
<input type="checkbox" class="faux-ui-facia" >
<div class="slide" slide="2" annot="This is the second slide title. Photo by S Charles.">
<img src="https://ununsplash.imgix.net/uploads/1413387158190559d80f7/6108b580?fit=crop&fm=jpg&q=75&w=600" alt="Slide 2">
</div>

/----start - css---/
.slide:after {
content: attr(slide);
display: block;
position: absolute;
bottom: 0;
}

Answer 1

http://www.javascriptkit.com/dhtmltutors/customattributes.shtml