Simple HR

HR alone : the line should fit exactly in the width of the page whatever. [yes]

HR noshade : this line should be filled with one color, not 3D-looking. [no]

HR width=100% : the line should fit exactly in the width of the page whatever (compared to HR). [yes]

The width attribute accepts % size.

HR width=50% : the line width should be exactly half the width of the page whatever, centered. [no]

HR width=50% align=left,center,right: the line should be positionned at the right place in the page (compared to leading and trailing HR). [no]

HR width=33% align=left,center,right: the line should be positionned at the right place in the page (compared to leading and trailing HR). [no]

The width attribute also accepts pixel size.

HR width=200 : the line width should be 200 pixels wide, centered. [no]

HR width=200 align=left,center,right: the line should be positionned at the right place in the page (compared to leading and trailing HR). [no]

The size attribute only accepts pixel size.

HR size=10, width=100%,50%,200 : each line should be 10 pixels thick. [no]

HR size=10 noshade, width=100%,50%,200 : each line should be 10 pixels thick. [no]

HR size=10% : should be ignored, or 10 pixels thick. [no]

Extreme/unusual dimensions

Shaded HR minimum dimensions are 2x2.
noshade HR minimum dimensions are 1x1.

HR size=1 : should be size=2. [no]

HR size=0 : should be size=2. [no]

HR size=1 noshade : should be size=1. [no]

HR size=0 noshade : should be size=1. [no]

HR widht=150% : should be width=100%. [no]

HR widht=3,2,1. [no]

HR widht=3,2,1 noshade. [no]

HR widht=3,2,1 size=10. [no]

HR widht=3,2,1 noshade size=10. [no]

HR widht=10 size=10. [no]

HR widht=10 noshade size=10. [no]

Positionning

2 HR width=100, width=50: the lines should be one _above_ the other. [no]

HR size=3,4,5,6,7,8,50. [no]

HR size=3. [no]