For循环在Javascript中生成多个XML请求

我需要访问一系列XML文档，并尝试使用动态生成每个请求的for循环来访问这些文档：

for (i=0;i<routes.length;i++) {
routeRequestURL = "http://webservices.nextbus.com/service/publicXMLFeed?command=routeConfig&a=sf-muni&r=" + routes[i].name + "&terse";
routeRequest.open("GET", routeRequestURL);
routeRequest.send();
routeResponse = routeRequest.responseXML;
route = routeResponse.getElementsByTagName("route")[0];
for (var j = 0; j < route.childNodes.length; j++) {
    if (route.childNodes[j].tagName == "stop") {
        routes[i].stops.push(new Stop(route.childNodes[j].getAttribute("tag"), route.childNodes[j].getAttribute("lat"), route.childNodes[j].getAttribute("lon")));
    }
  }
}

它不起作用。

有两件事：

在添加的

readystatechange

回调中，必须检查响应是否已完成加载

回调引入了闭包，这将导致对

i

的引用出现问题

以下代码应解决这两个问题：

routeRequest.onreadystatechange = (function(i) { return function() {
    if(routeRequest.readyState == 4 && routeRequest.status == 200) {
        routeResponse = routeRequest.responseXML;
        route = routeResponse.getElementsByTagName("route")[0];
        for (var j = 0; j < route.childNodes.length; j++) {
            if (route.childNodes[j].tagName == "stop") {
                routes[i].stops.push(new Stop(route.childNodes[j].getAttribute("tag"), route.childNodes[j].getAttribute("lat"), route.childNodes[j].getAttribute("lon")));
            }
        }
     }
}})(i);

routeRequest.onreadystatechange=（函数（i）{return function（）{
if（routeRequest.readyState==4&&routeRequest.status==200）{
RouterResponse=RouterRequest.responseXML；
route=RouterResponse.getElementsByTagName（“路由”）[0]；
对于（var j=0；j

您缺少一个

readystatechange

回调，因为请求是异步的。。。我将如何包括该回调？

routeRequest.onreadystatechange = (function(i) { return function() {
    if(routeRequest.readyState == 4 && routeRequest.status == 200) {
        routeResponse = routeRequest.responseXML;
        route = routeResponse.getElementsByTagName("route")[0];
        for (var j = 0; j < route.childNodes.length; j++) {
            if (route.childNodes[j].tagName == "stop") {
                routes[i].stops.push(new Stop(route.childNodes[j].getAttribute("tag"), route.childNodes[j].getAttribute("lat"), route.childNodes[j].getAttribute("lon")));
            }
        }
     }
}})(i);