如何在AJAX中使用AJAX？

I am using the following JavaScript to get the HTML.

$('#myHref').change(function() {
    var value = $('#myHref').val();
    $.get('get_project.php',{id:value},function(data) { 
        $('#projectDetail').html(data);
        $('#projectDetail').fadeIn('slow');
    }); 
}); 

I use some html in get_project.php as follow:

<select name="sn_id" id="sn_id" >
    <option>Data1</option>
    <option>Data2</option>
    .....
</select> 

I want to select menu and get returned on the basis of it. So again I add the following JavaScript to get value according to selected sn_id:

$('#sn_id').change(function() {
    var value = $('#sn_id').val();
    $.get('calculate_invest.php',{id:value},function(data) { 
        $('#show_me').html(data); 
    }); 
}); 

you are dynamically adding your "select" , then you need to add the event in the document, like this:

$(document).on('change','#sn_id', function() {
    var value = $('#sn_id').val();
    $.get('calculate_invest.php',{id:value},function(data) { 
        $('#show_me').html(data); 
    }); 
});