<div style="overflow:auto; height:50px; width:150px;">
<input type="checkbox" name="topic[]" value="$topicid"> $topics<br>
<input type="checkbox" name="topic[]" value="$topicid"> $topics<br>
<input type="checkbox" name="topic[]" value="$topicid"> $topics<br>
<input type="checkbox" name="topic[]" value="$topicid"> $topics<br>
<input type="checkbox" name="topic[]" value="$topicid"> $topics<br>
<input type="checkbox" name="topic[]" value="$topicid"> $topics<br>
<input type="checkbox" name="topic[]" value="$topicid"> $topics<br>
</div>