How i write id tag

Question

when I learning in app I have separate html CSS and js section to get output but in computer we can not have that sections so how can I use id tag

Answer 1

<p id="para">
.
.
.
</p>

if you wanna do anything with id's just use its selector with thm and that is "#"

#para{
property:value;
}

$(#para).blahblah

Answer 2

Id is not a tag it is an attribute