Question

使用此代码我可以计算下载速度：

var imgAddr = "http://upload.wikimedia.org/wikipedia/commons/2/2d/Snake_River_%285mb%29.jpg" + "?n=" + Math.random();
var startTime, endTime;
var download_size = 5*1024*1024;
var img = new Image();
img.onload = function () {
    endTime = (new Date()).getTime();
    ShowData();
}
startTime = (new Date()).getTime();
img.src = imgAddr;

function ShowData()
{
    var duration = (endTime - startTime) / 1000;
    var bitsLoaded = download_size * 8;
    var speedMbps = ((bitsLoaded / duration) / 1024 / 1024).toFixed(2);
    alert("Speed: " + speedMbps + " Mbps");
}

jsfiddle

如何将同一图像发送回虚拟php（不确定是否需要在我的服务器中存在服务器端脚本以“接受”POST请求）来计算上传强>速度

Answer 1

如果您想测试上传速度，我不明白为什么您要发送此特定图片。

我宁愿发送原始数据。

以下是一个例子：

var http = new XMLHttpRequest();
var startTime, endTime;
var url = "script_that_whill_handle_post.php";
var myData = "d="; // the raw data you will send
for(var i = 0 ; i < 1022 ; i++) //if you want to send 1 kb (2 + 1022 bytes = 1024b = 1kb). change it the way you want
{
    myData += "k"; // add one byte of data;
}

http.open("POST", url, true);

http.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
http.setRequestHeader("Content-length", myData .length);
http.setRequestHeader("Connection", "close");

http.onreadystatechange = function() {
    if(http.readyState == 4 && http.status == 200) {
        endTime = (new Date()).getTime();
        ShowData();
    }
}
startTime = (new Date()).getTime();
http.send(myData);

（使用相同的showData函数）

你也可以发送图像的数据而不是字母＆＃34; k＆＃34;多次，但它需要更多的代码，我没有看到任何改进这样做。

希望有所帮助

Answer 2

对于ajax上传：

var lastNow = new Date().getTime();
var lastKBytes = 0;
var xhr = new window.XMLHttpRequest();
xhr.upload.addEventListener("progress", function(e) {
    if (e.lengthComputable) {
        var now = new Date().getTime();
        var bytes = e.loaded;
        var total = e.total;
        var percent = bytes / total * 100;
        var kbytes = bytes / 1024;
        var mbytes = kbytes / 1024;
        var uploadedkBytes = kbytes - lastKBytes;
        var elapsed = (now - lastNow) / 1000;
        var kbps =  elapsed ? uploadedkBytes / elapsed : 0 ;
        lastKBytes = kbytes;
        lastNow = now;
        console.log(mbytes.toFixed(2) + "MB (" + percent.toFixed(2) + "%) " + kbps.toFixed(2) + "KB/s");
    }
}, false);

计算上传速度

2 个答案: