图像技巧很酷，但在我的测试中，它是在我想完成的一些ajax调用之前加载的。

2017年合适的解决方案是使用工人(http://caniuse.com/#feat=webworkers)。

工人看起来像这样:

/**
 * This function performs a synchronous request
 * and returns an object contain informations about the download
 * time and size
 */
function measure(filename) {
  var xhr = new XMLHttpRequest();
  var measure = {};
  xhr.open("GET", filename + '?' + (new Date()).getTime(), false);
  measure.start = (new Date()).getTime();
  xhr.send(null);
  measure.end = (new Date()).getTime();
  measure.len = parseInt(xhr.getResponseHeader('Content-Length') || 0);
  measure.delta = measure.end - measure.start;
  return measure;
}

/**
 * Requires that we pass a base url to the worker
 * The worker will measure the download time needed to get
 * a ~0KB and a 100KB.
 * It will return a string that serializes this informations as
 * pipe separated values
 */
onmessage = function(e) {
  measure0 = measure(e.data.base_url + '/test/0.bz2');
  measure100 = measure(e.data.base_url + '/test/100K.bz2');
  postMessage(
    measure0.delta + '|' +
    measure0.len + '|' +
    measure100.delta + '|' +
    measure100.len
  );
};

调用Worker的js文件:

var base_url = PORTAL_URL + '/++plone++experimental.bwtools';
if (typeof(Worker) === 'undefined') {
  return; // unsupported
}
w = new Worker(base_url + "/scripts/worker.js");
w.postMessage({
  base_url: base_url
});
w.onmessage = function(event) {
  if (event.data) {
    set_cookie(event.data);
  }
};

摘自我编写的Plone包的代码:

https://github.com/collective/experimental.bwtools/blob/master/src/experimental/bwtools/browser/static/scripts/

最好使用图像来测试速度。但是如果你必须处理zip文件，下面的代码可以工作。

var fileURL = "your/url/here/testfile.zip";

var request = new XMLHttpRequest();
var avoidCache = "?avoidcache=" + (new Date()).getTime();;
request.open('GET', fileURL + avoidCache, true);
request.responseType = "application/zip";
var startTime = (new Date()).getTime();
var endTime = startTime;
request.onreadystatechange = function () {
    if (request.readyState == 2)
    {
        //ready state 2 is when the request is sent
        startTime = (new Date().getTime());
    }
    if (request.readyState == 4)
    {
        endTime = (new Date()).getTime();
        var downloadSize = request.responseText.length;
        var time = (endTime - startTime) / 1000;
        var sizeInBits = downloadSize * 8;
        var speed = ((sizeInBits / time) / (1024 * 1024)).toFixed(2);
        console.log(downloadSize, time, speed);
    }
}

request.send();

对于小于10MB的文件，这将不能很好地工作。您必须在多次下载尝试中运行聚合结果。

我需要一个快速的方法来确定用户连接速度是否足够快，以启用/禁用我正在工作的网站中的某些功能，我做了这个小脚本，平均下载单个(小)图像所需的时间多次，它在我的测试中工作得相当准确，能够清楚地区分3G或Wi-Fi，例如，也许有人可以做一个更优雅的版本，甚至是jQuery插件。

var arrTimes = []; var i = 0; // start var timesToTest = 5; var tThreshold = 150; //ms var testImage = "http://www.google.com/images/phd/px.gif"; // small image in your server var dummyImage = new Image(); var isConnectedFast = false; testLatency(function(avg){ isConnectedFast = (avg <= tThreshold); /** output */ document.body.appendChild( document.createTextNode("Time: " + (avg.toFixed(2)) + "ms - isConnectedFast? " + isConnectedFast) ); }); /** test and average time took to download image from server, called recursively timesToTest times */ function testLatency(cb) { var tStart = new Date().getTime(); if (i<timesToTest-1) { dummyImage.src = testImage + '?t=' + tStart; dummyImage.onload = function() { var tEnd = new Date().getTime(); var tTimeTook = tEnd-tStart; arrTimes[i] = tTimeTook; testLatency(cb); i++; }; } else { /** calculate average of array items then callback */ var sum = arrTimes.reduce(function(a, b) { return a + b; }); var avg = sum / arrTimes.length; cb(avg); } }

尽管这是旧的和回答，我想分享的解决方案，我做出了它2020年的基础上的影子巫师说不再战争的解决方案

我只是将它合并到一个对象中，该对象具有随时运行的灵活性，并在指定的mbps高于或低于测量结果时运行回调。

可以在包含testConnectionSpeed对象后的任何位置启动测试

/**
* @param float    mbps               - Specify a limit of mbps.
* @param function more(float result) - Called if more mbps than specified limit.
* @param function less(float result) - Called if less mbps than specified limit.
*/
testConnectionSpeed.run(mbps, more, less)

例如:

var testConnectionSpeed = { imageAddr : "https://upload.wikimedia.org/wikipedia/commons/a/a6/Brandenburger_Tor_abends.jpg", // this is just an example, you rather want an image hosted on your server downloadSize : 2707459, // Must match the file above (from your server ideally) run:function(mbps_max,cb_gt,cb_lt){ testConnectionSpeed.mbps_max = parseFloat(mbps_max) ? parseFloat(mbps_max) : 0; testConnectionSpeed.cb_gt = cb_gt; testConnectionSpeed.cb_lt = cb_lt; testConnectionSpeed.InitiateSpeedDetection(); }, InitiateSpeedDetection: function() { window.setTimeout(testConnectionSpeed.MeasureConnectionSpeed, 1); }, result:function(){ var duration = (endTime - startTime) / 1000; var bitsLoaded = testConnectionSpeed.downloadSize * 8; var speedBps = (bitsLoaded / duration).toFixed(2); var speedKbps = (speedBps / 1024).toFixed(2); var speedMbps = (speedKbps / 1024).toFixed(2); if(speedMbps >= (testConnectionSpeed.max_mbps ? testConnectionSpeed.max_mbps : 1) ){ testConnectionSpeed.cb_gt ? testConnectionSpeed.cb_gt(speedMbps) : false; }else { testConnectionSpeed.cb_lt ? testConnectionSpeed.cb_lt(speedMbps) : false; } }, MeasureConnectionSpeed:function() { var download = new Image(); download.onload = function () { endTime = (new Date()).getTime(); testConnectionSpeed.result(); } startTime = (new Date()).getTime(); var cacheBuster = "?nnn=" + startTime; download.src = testConnectionSpeed.imageAddr + cacheBuster; } } // start test immediatly, you could also call this on any event or whenever you want testConnectionSpeed.run(1.5, function(mbps){console.log(">= 1.5Mbps ("+mbps+"Mbps)")}, function(mbps){console.log("< 1.5Mbps("+mbps+"Mbps)")} )

我成功地使用它来加载低分辨率的媒体慢网络连接。你必须玩一点，因为一方面，图像越大，测试就越合理，另一方面，对于慢速连接，测试将花费更长的时间，在我的情况下，我特别不希望慢速连接的用户加载大量mb。

我需要类似的东西，所以我写了https://github.com/beradrian/jsbandwidth。这是https://code.google.com/p/jsbandwidth/的重写。

其思想是通过Ajax进行两个调用，一个用于下载，另一个用于通过POST上传。

它应该与jQuery一起工作。ajax或Angular $http。

As I outline in this other answer here on StackOverflow, you can do this by timing the download of files of various sizes (start small, ramp up if the connection seems to allow it), ensuring through cache headers and such that the file is really being read from the remote server and not being retrieved from cache. This doesn't necessarily require that you have a server of your own (the files could be coming from S3 or similar), but you will need somewhere to get the files from in order to test connection speed.

也就是说，时间点带宽测试是出了名的不可靠，因为它们会受到其他窗口中正在下载的其他项目、服务器的速度、路由中的链接等的影响。但是你可以用这种方法得到一个大致的概念。