Populate dependant dropdowns from database tables

<script>
var BGArray = new Array ("bg staff 1", "bg staff 2", "bg staff 3")
var BHArray = new Array ("bh staff 1", "bh staff 2", "bh staff 3")
var ECArray = new Array ("ec staff 1", "ec staff 2", "ec staff 3")
var HDArray = new Array ("hd staff 1", "hd staff 2", "hd staff 3")
var PMArray = new Array ("pm staff 1", "pm staff 2", "pm staff 3")
var OtherArray = new Array ("Other")
 
function updateList(theForm, catName, subjListLength)
{
	for (var i=subjListLength + 1 ; i > 0 ; i-- )
	{
		theForm.Staff.options[i] = null
	}
	if( catName == "None"){
		var option0 = new Option("- Staff -", "None")
	}
	else{
		eval('var option0 = new Option("- Staff -", "None")')
	}
	NSL=0
	if (catName != "None") {
		eval("var NewSource = " + catName +"Array")
		NSL = NewSource.length
		for(var L = 0; L < NSL + 1; L++) {
			eval("var option" + [L + 1] + " = new Option(" + '"' + NewSource[L] + '", "' + NewSource[L] + '")') 
		}
	}
	for (var i=0; i < NSL + 1; i++) {
		eval("theForm.Staff.options[i]=option" + i)
		if (i==0) {
			theForm.Staff.options[i].selected=true
		}
	}
}
</script>
<form name='frm_sample' id='frm_sample' action='Process.asp' method='post'>
	<p>Location:
		<select name='Location' size="1" onChange="updateList(this.form, this.options[selectedIndex].value, this.form.Staff.length);">
			<option value="None" Selected >- Please Choose -</option>
			<option value="BG">Bgr</option>
			<option value="BH">Btn</option>
			<option value="EC" >Eau</option>
			<option value="HD" >Hld</option>
			<option value="PM" >Plm</option>
			<option value="Other" >Otr</option>
		</select>
	</p>
	<p>Staff:
		<select name="Staff" id="Staff">
			<option value="None" SELECTED>- Staff -</option>
		</select>
	</p>
</form>