Div height problem in IE

The following, as the only content in a file, is the requested 5px high in Mozilla and Opera, but 12px high in IE (5.0, 6.0 & 7.o):

<div class="dot" style="height:1px; border:1px solid red;"></div>

Divs in IE have a minimum height when the <div> is empty. There is a couple of ways to solve this:
1) Put a comment tag inside the div:
<div class="dot" style="height:1px; border:1px solid red;"><!-- --></div>

2) Add this to its style inside the div:
<div class="dot" style="font-size:2px; height:2px; border:1px solid red;"></div>