How to have one item as selected item in select element

Hi
I have a select element in my .aspx page:

<select id="t"></select>

I want to create option elements dynamically using Jquery:

$("<option>bb</option>").attr("value", "1").attr("selected", "selected").appendTo('#t');

I want to have one item as selected item when my select element load,but when i use code above I can`t see this result,in IE no item will show as selected element and in Fire Fox I can always see the first element.
What is the problem?What can I do?
Please help me.
Thanks in advance