[jQuery] Json works in firefox but not in ie

Hi,
I have this code and it works well in firefox but in IE it dosn't.
How do I make it work in IE?
If I put alert(options) inside the loop I get all the values I want so
this far it's working but outside the loop if i call alert(options)
nothing happens. why?

$("select#kod").change(function(){
$.getJSON("artnr-ajax.php",{value: $(this).val(), where: 'kod'},
function(j){
var options = '';
for (var i = 0; i < j.length; i++) {
options += '<option value="' + j[i].optionValue + '">' + j
[i].optionDisplay + '</option>';
}
$("select#beteckning").html(options);
})