javascript - 在 FOR 循环中等待上一个 AJAX 调用

Question

在循环和执行下一个调用之前，我如何等到上一个 ajax 调用完成？目前代码一直循环并一次执行所有 ajax 请求!

<script>
var busy;

function check(mailpass, proxy){
    var post_data = {};
    var post_json = "";

    post_data['mailpass'] = mailpass;
    post_data['proxy'] = '108.36.248.67:17786';
    post_json = JSON.stringify(post_data);

    jQuery.ajax({
        url: '/postdata' ,
        type: "POST",
        data: {params: post_json},
        success: function(data){
            var obj = JSON.parse(data);

            if(obj.error == 0){
                //
                $("#acc-live").append(obj.msg + "<br/>");
            } else if(obj.error == 1){
                //
                $("#socks-die").append(obj.msg+ "<br/>");   
            } else if(obj.error == 2){
                //
                $("#acc-die").append(obj.msg+ "<br/>"); 
            }
        }
    }); 

}
$(document).ready(function(){
    $("#submit").click(function(){
        var lines = $("#lines").val().split('\n');


        for(var i = 0;i < lines.length;i++){
            check(lines[i], '123');
        }

    });

});
</script>

Answer 1

您可以添加计数器 (currentIndex) 并稍微重新组织代码。

var busy;
var lines;
var currentIndex = 0;

function checkNext(){

    if( currentIndex >= lines.length ){
        console.log('all done');
        return;
    }

    var mailpass = lines[currentIndex];
    var proxy = '123';

    var post_data = {};
    var post_json = "";

    post_data['mailpass'] = mailpass;
    post_data['proxy'] = '108.36.248.67:17786';
    post_json = JSON.stringify(post_data);

    jQuery.ajax({
        url: '/postdata' ,
        type: "POST",
        data: {params: post_json},
        success: function(data){
            var obj = JSON.parse(data);

            if(obj.error == 0){
                //
                $("#acc-live").append(obj.msg + "<br/>");
            } else if(obj.error == 1){
                //
                $("#socks-die").append(obj.msg+ "<br/>");   
            } else if(obj.error == 2){
                //
                $("#acc-die").append(obj.msg+ "<br/>"); 
            }

            currentIndex++; //Increase the counter
            checkNext();
        }
    }); 

}
$(document).ready(function(){
    $("#submit").click(function(){
        lines = $("#lines").val().split('\n');          
        checkNext();
    });
});