Så här?
<script language="JavaScript" type="text/javascript">
function showLayer(Id){
if (document.all) {
document.all[Id].style.visibility = "visible";
} else if (document.layers){
document.layers[Id].visibility = "show";
} else if (document.getElementById){
document.getElementById(Id).style.visibility = "visible";
}
}
function hideLayer(Id){
if (document.all) {
document.all[Id].style.visibility = "hidden";
} else if (document.layers){
document.layers[Id].visibility = "hide";
} else if (document.getElementById){
document.getElementById(Id).style.visibility = "hidden";
}
}
current=false;
</script>
<form>
<select name="foo" onChange="if(current){ hideLayer(current); } current='beskrivning_'+this[this.selectedIndex].value; showLayer(current);">
<option value="">-- Välj --</option>
<option value="a">Ett val</option>
<option value="b">Ett val</option>
<option value="c">Ett val</option>
</select>
</form>
<div id="beskrivning_" style="position:absolute;top:100px;left:100px;visibility:hidden;"><!-- Ev text --></div>
<div id="beskrivning_a" style="position:absolute;top:100px;left:100px;visibility:hidden;">Text a</div>
<div id="beskrivning_b" style="position:absolute;top:100px;left:100px;visibility:hidden;">Text b</div>
<div id="beskrivning_c" style="position:absolute;top:100px;left:100px;visibility:hidden;">Text c</div>
