javascript - 如何在 for 循环(javascript)内的 ajax 调用内传递变量？

Question

使用 api，我需要第一个响应和第二个响应之一才能提供新页面。我面临的问题是我的变量 $x 总是设置为循环中最后一个 # 的值，即在这个特定情况下为 103。这是我的代码:

$.ajax({
dataType: 'text',
type: 'post',
url: 'getAllMessages.php',
success: function(responseData) {
    var newString = responseData;
    var newerString = newString.substring(0, newString.length - 1);
    $newObject = jQuery.parseJSON(newerString);
    //console.log($newObject);
    for($x = 0; $x < $newObject.messages.length; $x++){
        $.ajax({
            data: {clientFolderId: $newObject.messages[$x].clientFolderId, messageId: $newObject.messages[$x].messageId},
            dataType: 'text',
            type: 'post',
            url: 'testapi.php',
            success: function(responseData2){
                //alert($x);
                var newString2 = responseData2;
                var newerString2 = newString2.substring(0, newString2.length - 1);
                $newObject2 = jQuery.parseJSON(newerString2);
                if($newObject2.statistics.delivered > 1000){
                    console.log($newObject.messages[$x]);
                    console.log($newObject2);
                }
            },
            error: function(responseData2){
                alert('failure in testapi.php');
            }
        });
    }
},
error: function(responseData) {
    alert('failure in getAllMessages.php');
}

});

Answer 1

我的直觉告诉我，将 Ajax 调用嵌套在另一个功能范围内(感谢 Matt 的更正)将解决意外行为。我已经被这个烧毁了Object creation in loop broken; unrolled works

同样在这里，示例 #5:http://www.javascriptkit.com/javatutors/closures2.shtml

按照工程师给出的模式，

for($x = 0; $x < $newObject.messages.length; $x++){

   (function($x) {

    $.ajax({
        data: {clientFolderId: $newObject.messages[$x].clientFolderId, messageId: $newObject.messages[$x].messageId},
        dataType: 'text',
        type: 'post',
        url: 'testapi.php',
        success: function(responseData2){
            alert($x);
            var newString2 = responseData2;
            var newerString2 = newString2.substring(0, newString2.length - 1);
            $newObject2 = jQuery.parseJSON(newerString2);
            if($newObject2.statistics.delivered > 1000){
                console.log($newObject.messages[1]);
                console.log($newObject2);
            }
        },
        error: function(responseData2){
            alert('failure in testapi.php');
        }
    });

   })($x);
}