Java script problem in IE

Rails
1

i have a drop down and i populate it by java script and it looks like
this as below . the problem is in line “dd.add(new
Option(arr[i],arr[i]), null);” the error in IE is type mismatch. in
Mozilla it works fine …

java script
function toggle_category2_drop_down(type, sel,typ,fin)
{

if(type == ‘FastenerItem’)
{
var opt =
$(‘inventory_item_category_drop_down’).options[$(‘inventory_item_category_drop_down’).selectedIndex].text;
var arr = [];
switch (opt)
{
case ‘Binding’:
arr = [‘Comb’, ‘Coil’, ‘Twin Loop’, ‘Spiral-O’, ‘Velo’, ‘Wire’,
‘Thermal’, ‘Zip’, ‘Tape’, ‘Ring’, ‘Screw Post’, ‘Prong’, ‘Clasp’,
‘Tie’,‘Staple’];
arr.sort();
break
case ‘Reinforcing’:
arr = [‘Eyelet’, ‘Grommet’,‘Tape’];
arr.sort();
break
}

 if($('inventory_item_type_drop_down') != null)
{
  var dd = $('inventory_item_type_drop_down');
  dd.options.length = 0;
  for(var i=0;i<arr.length;i++)
  {
     dd.add(new Option(arr[i],arr[i]), null);
  }
  if(sel == '' || arr.indexOf(sel) ==  -1)
    {dd.selectedIndex = 0;}
  else
    {dd.selectedIndex = arr.indexOf(sel);}
}

}