Jquery: How to handle select

Below is example of how to use jquery select

$('#tag_item').on('change', function() {
  alert( "I am selected");
});


get selected value text:

$("#tag_select").change(function()
{
         var tag_value=$("#tag_select").val();
         if(tag_value!=-1)
     {
     var tag_name=$("#tag_select option:selected").text();
     add_tag_id(tag_value,tag_name);
     }
}