Topic:
Draws a horizontal rule across the page, usually 1 or 2 pixels wide. The horizontal rule automatically adjusts to the width of the browser's view area -- indenting itself from the left and right edges.
None
<HR> is legal within:
<BLOCKQUOTE> <BODY> <FORM> <PRE>
No markup can be used within <HR>, because it is a singleton tag that takes no attributes.
Wherever good design will benefit from placement of a horizontal rule -- typically to emphasize nature divisions between text items or topics, or to separate a page header and footer from the body -- the <HR> tag can add a lot to a page's looks.
Above the line.<BR>
<HR><BR>
Below the line.<BR>