Ajax请求使用循环

Question

Can you help me please to integrate this ajax code in a for loop?

I am trying to get the href from elements with class "links", and then use them to make httpRequests.
I have seen with firebug, that the httpRequests are sended, and i think the problem is somwere in the alertContents function. I struggled all day, but no result.

<a class="links" href="/1">Link1</a>
<a class="links" href="/2">Link2</a>
<a class="links" href="/3">Link3</a>

<script>
for(var i = 0; i < 2; i++) {
makeRequest(document.getElementsByClassName("links")[i].href);
}

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) {
  alert('Giving up :( Cannot create an XMLHTTP instance');
  return false;
}
httpRequest.onreadystatechange = alertContents;
httpRequest.open('GET', url);
httpRequest.send();
}

function alertContents() {
if (httpRequest.readyState === 4) {
  if (httpRequest.status === 200) {
    alert(httpRequest.responseText);
   // here i get the final value of the variable i
  } else {
    alert('There was a problem with the request.');
  }
}
}
</script>

Answer 1

I declared the variable so it is not global and moved your callback function inside of the makeRequest function.

for (var i = 0; i < 2; i++) {
    makeRequest(document.getElementsByClassName("links")[i].href);
}

function makeRequest(url) {

    var httpRequest;

    function alertContents() {
        if (httpRequest.readyState === 4) {
            if (httpRequest.status === 200) {
                alert(httpRequest.responseText);
                // here i get the final value of the variable i
            } else {
                alert('There was a problem with the request.');
            }
        }
    }

    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) {
        alert('Giving up :( Cannot create an XMLHTTP instance');
        return false;
    }
    httpRequest.onreadystatechange = alertContents;
    httpRequest.open('GET', url);
    httpRequest.send();

}