水平分線
align left / center / right noshade size width <hr align="left" size="10" width="50%" />
<hr align="center" noshade="" size="10" width="50% " />
<hr align="right" size="20" style="background: green;" width="100%" />
<hr align="center" noshade="" size="10" width="50% " />
<hr align="right" size="20" style="background: green;" width="100%" />