第二次加载时XMLHttpRequest状态为0 [英] XMLHttpRequest status 0 on second load

问题描述

当我尝试使用XMLHttpRequest从相同的域加载一些.txt格式的数据时，我遇到了一个有趣的问题。
我试图加载数据，解析它，然后将它存储在localStorage中

  var xmlhttp; 
 //代码为IE7 +，Firefox，Chrome，Opera，Safari 
 if（window.XMLHttpRequest）{
 xmlhttp = new XMLHttpRequest（）; 
} else {
 //代码为IE6，IE5 
 xmlhttp = new ActiveXObject（Microsoft.XMLHTTP）; 
} 
 
 var temp; 
 xmlhttp.onreadystatechange = function（）{
 if（xmlhttp.readyState == 4&& xmlhttp.status == 200）{
 temp = xmlhttp.responseText; 
 
} else {
 alert（readyState：+ xmlhttp.readyState +status：+ xmlhttp.status）; 
 
 
 xmlhttp.open（GET，data / somedata.txt，false）; 
 xmlhttp.send（）; 
  

此代码仅适用于清除历史记录和缓存;然而，第二次点击相同的链接时，我会收到Readystate：4，status 0。

/ p>

  if（！localStorage.somedata || localStorage.somedata.count（'：'）！== somedata.count（'： '））{
 localStorage.somedata = temp; 
} 
 window.somedata = JSON.parse（localStorage.somedata）; 
  

解决方案

状态码有两个原因。 / b>

1. 通过文件协议进行调用。


2. 页面正在刷新/导航，

在你的情况下，我会假定它是＃2。如果您使用按钮或链接进行Ajax调用，请确保使用 preventDefault 或返回false 。

I am experiencing an interesting issue when I am trying to load some data in .txt format from the same domain using XMLHttpRequest. I am trying to load the data, parse it and then store it in localStorage

var xmlhttp;
// code for IE7+, Firefox, Chrome, Opera, Safari
if (window.XMLHttpRequest){
    xmlhttp=new XMLHttpRequest();
}else{
    // code for IE6, IE5
    xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
}

var temp;
xmlhttp.onreadystatechange=function(){
    if (xmlhttp.readyState==4 && xmlhttp.status==200){
        temp = xmlhttp.responseText;

    }else{
        alert("readyState: " + xmlhttp.readyState + "status: " + xmlhttp.status);
    }
}
xmlhttp.open("GET","data/somedata.txt", false);
xmlhttp.send();

This code only works if I clean the history and cache; however, on second click of the same link, I would received "Readystate: 4, status 0" for some reason.

Does this has anything to do with localStorage?

if (!localStorage.somedata || localStorage.somedata.count(':') !== somedata.count(':')) {
  localStorage.somedata = temp;
}
window.somedata = JSON.parse(localStorage.somedata);

解决方案

There are two causes of status code of zero.

1. Making calls from the file protocol.
2. The page is refreshing/navigating away as the request is being made.

In your case I would assume it is #2. If you are using a button or a link to make the Ajax call, make sure to cancel the click action with either preventDefault or return false.

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