Div height in Firefox

Hello experts,

I have a simple div that has some PHP generated text inside and a predefined height in CSS.

Sometimes the text inside the div is larger than the div and in IE the div automatically adjuts the height so that the extra text fits in. But this doesn't happen in Firefox. Is there any way I could have the same behaviour in Firefox?

Here is the css for the div:
#daycell #date {
      border: 1px solid #000000;
      font-family: Arial, Helvetica, sans-serif;
      font-size: 12px;
      font-weight: bold;
      color: #FFFFFF;
      height: 30px;
      line-height: normal;
      text-align: center;
      background-color: #666666;
      margin-bottom: 4px;
}

And the div is something like:

<div id="date">
<?=$random_day_quote?>
</div>

Many thanks,
M