Can some one explain me, what I should use ?
div or semantic tag.
I see many dev use div in html5 doc.
Can you make me understand?
As you already know div is a block level element and html5 semantic tags are also & some of them not.
Its better to use semantic tag Cause this is the new feature of semantic tag to make reader clear about your code, I mean markup.
So, the answer is:
Use semantic whenever possible but if you need div /span you can use them.