为什么mongoDB使用objectID？(Why mongoDB uses objectID?)

 我用了 
 
  type: "GET",
  url: "http://stackoverflow.com/questions/32554239/ajax-post-without-refresh", 
 
 而不是你的 
 
   type: "POST",
  url: "http://****/new/action.php",  
 
 它工作正常。 （只需点击“运行代码段”，它会显示错误，因为该网址不支持跨域） 
 
 
 
 
  
$(document).ready(function() {  
  $("form#iscrizione").submit(function(){   
    var ordine = $("#ordine").val();  
    var cognome = $("#cognome").val();
    $.ajax({  
      type: "GET",
      url: "http://stackoverflow.com/questions/32554239/ajax-post-without-refresh",  
      data: "cognome=" + cognome + "&ordine=" + ordine,
      dataType: "html",
      success: function(risposta) {  
        $("div#risposta").html(risposta);  
        alert("ok!");
      },
      error: function(){
              alert("Chiamata fallita!!!");
}
    }); 
    return false;  
  });
});
 
  
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<form id="iscrizione"> 
  
  <input type="text" value="get" id="cognome"><input type="text" value="get" id="ordine"><input type="submit" value="get"></form><div id="risposta"></div>
 
 
 
 

I used 
 
  type: "GET",
  url: "http://stackoverflow.com/questions/32554239/ajax-post-without-refresh", 
 
instead of your 
 
   type: "POST",
  url: "http://****/new/action.php",  
 
AND it works fine. (Just click on "Run snippet", it shows an error because the url doesn't support cross-domain) 
 
 
 
 
  
$(document).ready(function() {  
  $("form#iscrizione").submit(function(){   
    var ordine = $("#ordine").val();  
    var cognome = $("#cognome").val();
    $.ajax({  
      type: "GET",
      url: "http://stackoverflow.com/questions/32554239/ajax-post-without-refresh",  
      data: "cognome=" + cognome + "&ordine=" + ordine,
      dataType: "html",
      success: function(risposta) {  
        $("div#risposta").html(risposta);  
        alert("ok!");
      },
      error: function(){
              alert("Chiamata fallita!!!");
}
    }); 
    return false;  
  });
});
 
  
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<form id="iscrizione"> 
  
  <input type="text" value="get" id="cognome"><input type="text" value="get" id="ordine"><input type="submit" value="get"></form><div id="risposta"></div>