javascript - Rails Jquery chained selects -

i'm trying setup jquery chained select when create new product

1. gender
2. category
3. subcategory

the gender , category chaining, minus subcategory dont appear!

please give light? thank's

$(document).ready(function () {      var $gender, $category;      $gender = $('input[id^="product_gender_id"]');     $category = $('#product_category_id');       //radio can response 'click' event, rather select event wrote before.     $gender.click(function () {          var gender = $('input[id^="product_gender_id"]:checked').val();          if (gender == 1);          else if (gender == 2);           jquery.get('/products/update_category_select/' + gender, function(data){             $("#productcategories").html(data);         })     });       $category.change(function() {         // make post call , replace content          var category = $('select#product_category_id :selected').val();          if(category == "") category="0";         jquery.get('/products/update_subcategory_select/' + category, function(data){             $("#productsubcategories").html(data);         })         return false;     });   });