Javascript 链接下拉列表未填充

我正在做一个链式下拉列表来过滤数据。我的第一个下拉列表是填充良好，但第二个似乎不起作用。我一直在努力寻找这个问题，但没有结果。我正在使用javascript使链正常工作

模型

看法

Javascript

(function() {
    var httpRequest;
    dropper =document.getElementById("subdrop");
    dropper.onchange = function() {
        makeRequest('localhost/highball061516/atis/xing/ajaxdrop?subdivision=' + dropper.value);
    };

    function makeRequest(url) {
        if (window.XMLHttpRequest) { // Mozilla, Safari, ...
            httpRequest = new XMLHttpRequest();
        } else if (window.ActiveXObject) { // IE
            try {
                httpRequest = new ActiveXObject("Msxml2.XMLHTTP");
            }
            catch (e) {
                try {
                    httpRequest = new ActiveXObject("Microsoft.XMLHTTP");
                } catch (e) {}
            }
        }
    }
    if (!httpRequest) {
        altert('Giving up :( Cannot create an XMLHTTP instance');
            return false;
    }
    httpRequest.onreadystatechange = alertContents;
    httpRequest.open('GET', url);
    httpRequest.setRequestHeader('X-Requested-With','XMLHttpRequest');
        httpRequest.send();
    }

    function alertContents(){
        if (httpRequest.readyState === 4) {
            if (httpRequest.Status === 200){
                var data = JSON.parse(httpRequest.response);
                var select = document.getElementById('xingdrop');
                if(emptySelect(select)){
                    for (var i = 0; i < data.sub_xings.length; i++){
                        var el = document.createElement("option");
                            el.textContent = data.sub_xings[i].Street;
                            el.value = data.sub_xings[i].Street;
                            select.appendChild(el);
                    }
                }
            }else{
                alert('There was a problem with the request.');
            }
        }
    }

    function emptySelect(select_object){
        while(select_object.options.length > 0){
            select_object.remove(0);
        }
        return 1;
    }
})();

（函数（）{
var-httpRequest；
滴管=document.getElementById（“子滴管”）；
dropper.onchange=函数（）{
makeRequest（'localhost/highball061516/atis/xing/ajaxdrop？subsection='+droper.value）；
};
函数makeRequest（url）{
如果（window.XMLHttpRequest）{//Mozilla，Safari。。。
httpRequest=新的XMLHttpRequest（）；
}如果（window.ActiveXObject）{//IE
试一试{
httpRequest=新的ActiveXObject（“Msxml2.XMLHTTP”）；
}
捕获（e）{
试一试{
httpRequest=新的ActiveXObject（“Microsoft.XMLHTTP”）；
}捕获（e）{}
}
}
}
如果（！httpRequest）{
altert（‘放弃：（无法创建XMLHTTP实例’）；
返回false；
}
httpRequest.onreadystatechange=alertContents；
httpRequest.open（'GET'，url）；
setRequestHeader（'X-request-With'，'XMLHttpRequest'）；
httpRequest.send（）；
}
函数alertContents（）{
if（httpRequest.readyState==4）{
if（httpRequest.Status==200）{
var data=JSON.parse（httpRequest.response）；
var select=document.getElementById（'xingdrop'）；
如果（清空选择（选择））{
对于（var i=0；i0）{
选择对象。删除（0）；
}
返回1；
}
})();

将

.Status

更改为

.Status

位于：

if (httpRequest.Status === 200){

检查此参考：

更新：我发现代码中的大括号有问题

这个版本应该可以正常工作

(function() {
  var httpRequest;
  dropper = document.getElementById("subdrop");
  dropper.onchange = function() {
    makeRequest('localhost/highball061516/atis/xing/ajaxdrop?subdivision=' + dropper.value);
  };

  function makeRequest(url) {
    if (window.XMLHttpRequest) { // Mozilla, Safari, ...
      httpRequest = new XMLHttpRequest();
    } else if (window.ActiveXObject) { // IE
      try {
        httpRequest = new ActiveXObject("Msxml2.XMLHTTP");
      } catch (e) {
        try {
          httpRequest = new ActiveXObject("Microsoft.XMLHTTP");
        } catch (e) {}
      }
    }
  }
  if (!httpRequest) {
    altert('Giving up :( Cannot create an XMLHTTP instance');
    return false;
  }
  httpRequest.onreadystatechange = alertContents;
  httpRequest.open('GET', url);
  httpRequest.setRequestHeader('X-Requested-With', 'XMLHttpRequest');
  httpRequest.send();

  function alertContents() {
    if (httpRequest.readyState === 4) {
      if (httpRequest.status === 200) {
        var data = JSON.parse(httpRequest.response);
        var select = document.getElementById('xingdrop');
        if (emptySelect(select)) {
          for (var i = 0; i < data.sub_xings.length; i++) {
            var el = document.createElement("option");
            el.textContent = data.sub_xings[i].Street;
            el.value = data.sub_xings[i].Street;
            select.appendChild(el);
          }
        }
      } else {
        alert('There was a problem with the request.');
      }
    }
  }

  function emptySelect(select_object) {
    while (select_object.options.length > 0) {
      select_object.remove(0);
    }
    return 1;
  }
})();

（函数（）{
var-httpRequest；
滴管=document.getElementById（“子滴管”）；
dropper.onchange=函数（）{
makeRequest（'localhost/highball061516/atis/xing/ajaxdrop？subsection='+droper.value）；
};
函数makeRequest（url）{
如果（window.XMLHttpRequest）{//Mozilla，Safari。。。
httpRequest=新的XMLHttpRequest（）；
}如果（window.ActiveXObject）{//IE
试一试{
httpRequest=新的ActiveXObject（“Msxml2.XMLHTTP”）；
}捕获（e）{
试一试{
httpRequest=新的ActiveXObject（“Microsoft.XMLHTTP”）；
}捕获（e）{}
}
}
}
如果（！httpRequest）{
altert（‘放弃：（无法创建XMLHTTP实例’）；
返回false；
}
httpRequest.onreadystatechange=alertContents；
httpRequest.open（'GET'，url）；
setRequestHeader（'X-request-With'，'XMLHttpRequest'）；
httpRequest.send（）；
函数alertContents（）{
if（httpRequest.readyState==4）{
if（httpRequest.status==200）{
var data=JSON.parse（httpRequest.response）；
var select=document.getElementById（'xingdrop'）；
如果（清空选择（选择））{
对于（var i=0；i0）{
选择对象。删除（0）；
}
返回1；
}
})();

更新2:使用自定义帮助程序XMLHttpRequest函数

(function ()
{
    var httpRequest;
    var dropper = document.getElementById("subdrop");
    dropper.onchange = function ()
    {
        makeRequest(
        {
            url: 'localhost/highball061516/atis/xing/ajaxdrop?subdivision=' + dropper.value,
            type: 'GET',
            callback: alertContents
        });
    };
    function makeRequest(options)
    {
        httpRequest = new XMLHttpRequest() || new window.ActiveXObject("Microsoft.XMLHTTP");
        options.contentType = "application/x-www-form-urlencoded";
        httpRequest.open(options.type, options.url, options.async || true);
        httpRequest.setRequestHeader("Content-Type", options.contentType);
        httpRequest.setRequestHeader("X-Requested-With","XMLHttpRequest");
        httpRequest.send((options.type == "POST") ? options.data : null);
        httpRequest.onreadystatechange = options.callback;
        return httpRequest;
    }
    function alertContents()
    {
        if (httpRequest.readyState === 4)
        {
            if (httpRequest.status === 200)
            {
                var data = JSON.parse(httpRequest.response);
                console.log(data);
                var select = document.getElementById('xingdrop');
                if (emptySelect(select))
                {
                    for (var i = 0; i < data.sub_xings.length; i++)
                    {
                        var el = document.createElement("option");
                        el.textContent = data.sub_xings[i].Street;
                        el.value = data.sub_xings[i].Street;
                        select.appendChild(el);
                    }
                }
            }
            else
            {
                alert('There was a problem with the request.');
            }
        }
    }
    function emptySelect(select_object)
    {
        while (select_object.options.length > 0)
        {
            select_object.remove(0);
        }
        return 1;
    }
})();

（函数（）
{
var-httpRequest；
var dropper=document.getElementById（“子drop”）；
dropper.onchange=函数（）
{
提出请求(
{
url:'localhost/highball061516/atis/xing/ajaxdrop？subsection='+droper.value，
键入：“GET”，
回调：alertContents
});
};
函数makeRequest（选项）
{
httpRequest=new-XMLHttpRequest（）| | new window.ActiveXObject（“Microsoft.XMLHTTP”）；
options.contentType=“application/x-www-form-urlencoded”；
打开（options.type、options.url、options.async | | true）；
setRequestHeader（“内容类型”，options.contentType）；
setRequestHeader（“X-request-With”，“XMLHttpRequest”）；
httpRequest.send（（options.type==“POST”）？options.data:null）；
httpRequest.onreadystatechange=options.callback；
返回httpRequest；
}
函数alertContents（）
{
if（httpRequest.readyState==4）
{
if（httpRequest.status==200）
{
var data=JSON.parse（httpRequest.response）；
控制台日志（数据）；
var select=document.getElementById（'xingdrop'）；
如果（清空选择（选择））
{
对于（var i=0；iif (httpRequest.Status === 200){

(function() {
  var httpRequest;
  dropper = document.getElementById("subdrop");
  dropper.onchange = function() {
    makeRequest('localhost/highball061516/atis/xing/ajaxdrop?subdivision=' + dropper.value);
  };

  function makeRequest(url) {
    if (window.XMLHttpRequest) { // Mozilla, Safari, ...
      httpRequest = new XMLHttpRequest();
    } else if (window.ActiveXObject) { // IE
      try {
        httpRequest = new ActiveXObject("Msxml2.XMLHTTP");
      } catch (e) {
        try {
          httpRequest = new ActiveXObject("Microsoft.XMLHTTP");
        } catch (e) {}
      }
    }
  }
  if (!httpRequest) {
    altert('Giving up :( Cannot create an XMLHTTP instance');
    return false;
  }
  httpRequest.onreadystatechange = alertContents;
  httpRequest.open('GET', url);
  httpRequest.setRequestHeader('X-Requested-With', 'XMLHttpRequest');
  httpRequest.send();

  function alertContents() {
    if (httpRequest.readyState === 4) {
      if (httpRequest.status === 200) {
        var data = JSON.parse(httpRequest.response);
        var select = document.getElementById('xingdrop');
        if (emptySelect(select)) {
          for (var i = 0; i < data.sub_xings.length; i++) {
            var el = document.createElement("option");
            el.textContent = data.sub_xings[i].Street;
            el.value = data.sub_xings[i].Street;
            select.appendChild(el);
          }
        }
      } else {
        alert('There was a problem with the request.');
      }
    }
  }

  function emptySelect(select_object) {
    while (select_object.options.length > 0) {
      select_object.remove(0);
    }
    return 1;
  }
})();

(function ()
{
    var httpRequest;
    var dropper = document.getElementById("subdrop");
    dropper.onchange = function ()
    {
        makeRequest(
        {
            url: 'localhost/highball061516/atis/xing/ajaxdrop?subdivision=' + dropper.value,
            type: 'GET',
            callback: alertContents
        });
    };
    function makeRequest(options)
    {
        httpRequest = new XMLHttpRequest() || new window.ActiveXObject("Microsoft.XMLHTTP");
        options.contentType = "application/x-www-form-urlencoded";
        httpRequest.open(options.type, options.url, options.async || true);
        httpRequest.setRequestHeader("Content-Type", options.contentType);
        httpRequest.setRequestHeader("X-Requested-With","XMLHttpRequest");
        httpRequest.send((options.type == "POST") ? options.data : null);
        httpRequest.onreadystatechange = options.callback;
        return httpRequest;
    }
    function alertContents()
    {
        if (httpRequest.readyState === 4)
        {
            if (httpRequest.status === 200)
            {
                var data = JSON.parse(httpRequest.response);
                console.log(data);
                var select = document.getElementById('xingdrop');
                if (emptySelect(select))
                {
                    for (var i = 0; i < data.sub_xings.length; i++)
                    {
                        var el = document.createElement("option");
                        el.textContent = data.sub_xings[i].Street;
                        el.value = data.sub_xings[i].Street;
                        select.appendChild(el);
                    }
                }
            }
            else
            {
                alert('There was a problem with the request.');
            }
        }
    }
    function emptySelect(select_object)
    {
        while (select_object.options.length > 0)
        {
            select_object.remove(0);
        }
        return 1;
    }
})();

    function get_xing_list(){
    $this->db->select('street');
    $query = $this->db->get('xings');

    if ($query->num_rows() > 0)
    {
      return $query->result();
    }else{
      return 'No Xings Found';
    }
}  

    function get_sub_list(){
        $this->db->select('subdname');
        $query = $this->db->get('subdivisions');

        if ($query->num_rows() > 0)
            {
                return $query->result();
            }else{
                return 'No Subs Found';
            }
    }

    function get_sub_xings($subdname){
        $this->db->select('street');
        $this->db->where('subdname', $subdname);
        $query = $this->db->get('xings');
        log_message('info', "Value of subdivision was $subdname");
            if ($query->num_rows() > 0)
            {
                return $query->result_array();
            }else{
                return 'No Subs Found';
            }