HEAD section:

<script language = "JavaScript">
var Chevrolet = new Array("Camaro","Corvette","Cavalier","Impala","Malibu","Monte Carlo","Prizm");
var Ford = new Array("Crown Victoria","Escort","Focus","Mustang","Taurus","Thunderbird","");
var Oldsmobile = new Array("Alero","Aurora","Intrigue","","","","");
var Pontiac = new Array("Bonneville","Firebird","Grand Am","Grand Prix","Sunfire","","");

function oselect(Title)
{
var mselect = window.document.form1.Model;
var boxx = eval(Title);
setopt(window.document.form1.Model, boxx);
}
function setopt(ychoice, boxx)
{
for (loop=0; loop < ychoice.options.length; loop++)
{
ychoice.options[loop].text = boxx[loop];
}
}
</script>

BODY:

<form name="form1">
<select name="Make"
onChange="oselect(window.document.form1.Make.options[selectedIndex].text);">
<option selected>Chevrolet
<option>Ford
<option>Oldsmobile
<option>Pontiac
</select>
<select name="Model" multiple size="7">
<option>Camaro
<option>Cavalier
<option>Corvette
<option>Impala
<option>Malibu
<option>Monte Carlo
<option>Prizm
</select>
</form>