var spaces="----";  
var category_name="category";
    var category_text=spaces+category_name;
    alert(category_text);
    $('select').append($("<option>").attr({'value' : inserted_id , 'label' : category_name}).text(category_text));

This code includes option to my listbox.

The problem in Internet Explorer 7. The option is included, but the expected display is '----category'. But Internet Explorer 7 displays only category in options. Since I am using tree order I need to have hyphens before some category. How can I solve it in Internet Explorer 7?