I've been trying to populate the second select list based upon the selection in the first. I have tried two methods of supplying the object information. Even after adding a default case with an alert the alert did not post. JSfiddle and jslint say my code is fine except for the missing default case. Any help would be much appreciated, thank you in advance.

HTML/JavaScript
Code:
<script type="text/javascript">
	function SetLengths()
	{
	var bnlength = new Array();
		bnlength[0][0] = {value:"n16", text:"16 Inches"};
		bnlength[0][1] = {value:"n18", text:"18 Inches"};
		bnlength[0][2] = {value:"n20", text:"20 Inches"};
		bnlength[0][3] = {value:"n22", text:"22 Inches"};
		bnlength[0][4] = {value:"n24", text:"24 Inches"};
		bnlength[0][5] = {value:"o24", text:"*Over 24 Inches"};
		bnlength[1][0] = {value:"es", text:"Extra-Small"};
		bnlength[1][1] = {value:"ss", text:"Small"};
		bnlength[1][2] = {value:"mm", text:"Medium"};
		bnlength[1][3] = {value:"ll", text:"Large"};
		bnlength[1][4] = {value:"el", text:"Extra-Large"};
	var bnsel = document.getElementById('bnselect');
	var lengthsel = document.getElementById('lengthselect');
	var _val = bnsel.options[bnsel.selectedIndex].value;
	bnsel.length = 1;
		var op1 = document.createElement('option');
		var op2 = document.createElement('option');
		var op3 = document.createElement('option');
		var op4 = document.createElement('option');
		var op5 = document.createElement('option');
		var op6 = document.createElement('option');
	switch(_val){
		case "necklace":
			op1.innerHTML = bnlength[0][0].text;
			op1.value = bnlength[0][0].value;
			lengthsel.appendChild(op1);
			op2.innerHTML = bnlength[0][1].text;
			op2.value = bnlength[0][1].value;
			lengthsel.appendChild(op2);
			op3.innerHTML = bnlength[0][2].text;
			op3.value = bnlength[0][2].value;
			lengthsel.appendChild(op3);
			op4.innerHTML = bnlength[0][3].text;
			op4.value = bnlength[0][3].value;
			lengthsel.appendChild(op4);
			op5.innerHTML = bnlength[0][4].text;
			op5.value = bnlength[0][4].value;
			lengthsel.appendChild(op5);
			op6.innerHTML = bnlength[0][5].text;
			op6.value = bnlength[0][5].value;
			lengthsel.appendChild(op6);
		break;
		case "bracelet":
			op1.innerHTML = "Extra-Small";
			op1.value = "es";
			lengthsel.appendChild(op1);
			op2.innerHTML = "Small";
			op2.value = "ss";
			lengthsel.appendChild(op2);
			op3.innerHTML = "Medium";
			op3.value = "mm";
			lengthsel.appendChild(op3);
			op4.innerHTML = "Large";
			op4.value = "ll";
			lengthsel.appendChild(op4);
			op5.innerHTML = "Extra-Large";
			op5.value = "el";
			lengthsel.appendChild(op5);
		break;
		}
	}
</script>
<br/>
<p>Select Type:</p>
<select ID="bnselect" onchange=SetLengths()>
	<option selected="selected" disabled>--Select Type--</option>
	<option value="necklace">Necklace</option>
	<option value="bracelet">Bracelet</option>
</select>
<br/>
<p>Select Length:</p>
<select ID="lengthselect">
	<option selected="selected" disabled>--Select Length--</option>
</select>