JavaScript-数组中每个元素的HTTP请求

Question

I have a script that sends HTTP requests to a website to get documents, the document IDs are kept in an array. I want to send a request for each array element and return a message based on the status from the HEAD (eg 200 OK).

The problem I have is that when I loop through the URL array, multiple requests are sent using only the last array element, no other element is used.

Code:

//send http request
function sendRequest(url) {
  var newRequest = new XMLHttpRequest();

  newRequest.onreadystatechange = function() {
    if(newRequest.readyState == 4) {
      if(newRequest.status == 200) {    
        console.log("loaded: " + url);
      } else {
        console.log("Failed to load: " + url);
      }
    }
  }

  newRequest.open("HEAD", url);
  newRequest.send();
}

//send request for each url in array
for(var i = 0; i < urlArray.length; i++) {
  //get document id and append to link
  var address = "https://www.adsa.co.uk/library.dr/docs.aspx?id=" + 
                urlArray[i];
  //console.log(address + "\n");
  sendRequest(address);
}

Output (74 is the value of the last element in the array):
This console message is produced urlArray.length times:

Failed to load: https://www.adsa.co.uk/library.dr/docs.aspx?id=74

Any ideas why the sendRequest() is not sent for each array element?

Answer 1

Chrome（和Firefox）抱怨SSL证书无效，因此无法连接：

Failed to load resource: net::ERR_INSECURE_RESPONSE

Answer 2

Thanks to @Chris in the comments for alerting me to try jsfiddle.

The above code executes as it should, it iterates over the array and sends an HTTP request for each array element. The issue was with repl.it , a read-eval-print-loop coding environment. Switching to jsbin and jsfiddle produced expected results.

Read about REPL .