computer_glamour
/
librespeed-mirror
réplica de https://github.com/librespeed/speedtest


			
				
					
						
						
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							<!doctype html>
<html>
  <head>
    <link rel="shortcut icon" href="favicon.ico" />
    <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no, user-scalable=no" />
    <meta charset="UTF-8" />
    <title>LibreSpeed - Stability Test</title>
    <style type="text/css">
      html,
      body {
        border: none;
        padding: 0;
        margin: 0;
        background: #ffffff;
        color: #202020;
      }
      body {
        text-align: center;
        font-family: "Roboto", sans-serif;
      }
      h1 {
        color: #404040;
      }
      nav {
        margin-bottom: 1em;
      }
      nav a {
        color: #6060aa;
        text-decoration: none;
        font-size: 0.95em;
      }
      nav a:hover {
        text-decoration: underline;
      }
      #controls {
        margin: 1em auto;
      }
      #durationSelect,
      #targetSelect {
        font-size: 1em;
        padding: 0.3em 0.5em;
        margin-right: 1em;
      }
      #startBtn {
        display: inline-block;
        margin: 0 auto;
        color: #6060aa;
        background-color: rgba(0, 0, 0, 0);
        border: 0.15em solid #6060ff;
        border-radius: 0.3em;
        transition: all 0.3s;
        box-sizing: border-box;
        width: 8em;
        height: 3em;
        line-height: 2.7em;
        cursor: pointer;
        box-shadow:
          0 0 0 rgba(0, 0, 0, 0.1),
          inset 0 0 0 rgba(0, 0, 0, 0.1);
      }
      #startBtn:hover {
        box-shadow:
          0 0 2em rgba(0, 0, 0, 0.1),
          inset 0 0 1em rgba(0, 0, 0, 0.1);
      }
      #startBtn:before {
        content: "Start";
      }
      #startBtn.running {
        background-color: #ff3030;
        border-color: #ff6060;
        color: #ffffff;
      }
      #startBtn.running:before {
        content: "Abort";
      }
      #resetBtn {
        display: inline-block;
        color: #808080;
        background-color: rgba(0, 0, 0, 0);
        border: 0.15em solid #a0a0a0;
        border-radius: 0.3em;
        transition: all 0.3s;
        box-sizing: border-box;
        width: 6em;
        height: 3em;
        line-height: 2.7em;
        cursor: pointer;
        margin-left: 0.5em;
        box-shadow:
          0 0 0 rgba(0, 0, 0, 0.1),
          inset 0 0 0 rgba(0, 0, 0, 0.1);
      }
      #resetBtn:hover {
        box-shadow:
          0 0 2em rgba(0, 0, 0, 0.1),
          inset 0 0 1em rgba(0, 0, 0, 0.1);
      }
      #serverArea {
        margin: 0.8em 0;
      }
      #server {
        font-size: 1em;
        padding: 0.2em;
      }
      #test {
        margin-top: 2em;
        margin-bottom: 2em;
      }
      div.testGroup {
        display: block;
        margin: 0 auto;
      }
      div.testArea2 {
        display: inline-block;
        width: 10em;
        height: 7em;
        position: relative;
        box-sizing: border-box;
        text-align: center;
      }
      div.testArea2 div.testName {
        display: block;
        text-align: center;
        font-size: 1.4em;
      }
      div.testArea2 div.meterText {
        display: inline-block;
        font-size: 2.5em;
      }
      div.meterText:empty:before {
        content: "0.00";
      }
      div.testArea2 div.unit {
        display: inline-block;
      }
      #rating {
        font-size: 1.3em;
        font-weight: bold;
        margin: 0.5em 0;
      }
      #rating.great {
        color: #2ecc71;
      }
      #rating.good {
        color: #27ae60;
      }
      #rating.poor {
        color: #e67e22;
      }
      #rating.bad {
        color: #e74c3c;
      }
      #rating.none {
        color: #808080;
      }
      #chartContainer {
        margin: 1em auto;
        width: 95%;
        max-width: 60em;
        position: relative;
      }
      #pingChart {
        width: 100%;
        height: 280px;
        border: 1px solid #e0e0e0;
        border-radius: 4px;
        background: #fafafa;
      }
      #optionalControls {
        margin: 1.5em auto;
        max-width: 40em;
      }
      #optionalControls label {
        display: block;
        margin: 0.5em 0;
      }
      #alertThreshold {
        vertical-align: middle;
        width: 200px;
      }
      #downloadCsvBtn {
        margin-top: 0.8em;
        font-size: 0.9em;
        padding: 0.4em 1em;
        cursor: pointer;
        border: 1px solid #6060aa;
        background: none;
        color: #6060aa;
        border-radius: 0.3em;
      }
      #downloadCsvBtn:hover {
        background: #6060aa;
        color: #ffffff;
      }
      .footer {
        margin: 2em 0 1em;
      }
      .footer a {
        color: #808080;
        font-size: 0.85em;
      }
      @media all and (max-width: 40em) {
        body {
          font-size: 0.8em;
        }
        #pingChart {
          height: 200px;
        }
      }
      @media all and (prefers-color-scheme: dark) {
        html,
        body {
          background: #202020;
          color: #f4f4f4;
          color-scheme: dark;
        }
        h1 {
          color: #e0e0e0;
        }
        nav a {
          color: #9090ff;
        }
        #pingChart {
          border-color: #404040;
          background: #1a1a1a;
        }
        a {
          color: #9090ff;
        }
        #startBtn {
          color: #9090ff;
          border-color: #7070ff;
        }
        #startBtn.running {
          background-color: #ff3030;
          border-color: #ff6060;
          color: #ffffff;
        }
        #resetBtn {
          color: #a0a0a0;
          border-color: #606060;
        }
        #downloadCsvBtn {
          color: #9090ff;
          border-color: #9090ff;
        }
        #downloadCsvBtn:hover {
          background: #9090ff;
          color: #202020;
        }
        .footer a {
          color: #a0a0a0;
        }
      }
    </style>
  </head>
  <body>
    <h1>LibreSpeed - Stability Test</h1>
    <nav><a href="./">&larr; Speed Test</a></nav>

    <div id="controls">
      <select id="durationSelect">
        <option value="60">60 Seconds</option>
        <option value="90">90 Seconds</option>
        <option value="120">2 Minutes</option>
        <option value="180">3 Minutes</option>
        <option value="300">5 Minutes</option>
      </select>
      <select id="targetSelect">
        <option value="">Local Server</option>
        <option value="https://www.google.com/generate_204">Google</option>
        <option value="https://www.cloudflare.com/cdn-cgi/trace">Cloudflare</option>
        <option value="https://www.apple.com/library/test/success.html">Apple</option>
      </select>
      <div id="startBtn" onclick="startStop()"></div>
      <div id="resetBtn" onclick="resetTest()">Reset</div>
    </div>

    <div id="serverArea" style="display: none">
      Server:
      <select id="server" onchange="onServerChange(this.value)"></select>
    </div>

    <div id="rating" class="none">--</div>

    <div id="test">
      <div class="testGroup">
        <div class="testArea2">
          <div class="testName">Current</div>
          <div id="statCurrent" class="meterText" style="color: #aa6060"></div>
          <div class="unit">ms</div>
        </div>
        <div class="testArea2">
          <div class="testName">Average</div>
          <div id="statAvg" class="meterText" style="color: #aa6060"></div>
          <div class="unit">ms</div>
        </div>
        <div class="testArea2">
          <div class="testName">Jitter</div>
          <div id="statJitter" class="meterText" style="color: #aa6060"></div>
          <div class="unit">ms</div>
        </div>
      </div>
      <div class="testGroup">
        <div class="testArea2">
          <div class="testName">Min</div>
          <div id="statMin" class="meterText"></div>
          <div class="unit">ms</div>
        </div>
        <div class="testArea2">
          <div class="testName">Max</div>
          <div id="statMax" class="meterText"></div>
          <div class="unit">ms</div>
        </div>
        <div class="testArea2">
          <div class="testName">Failed Requests</div>
          <div id="statLoss" class="meterText"></div>
          <div class="unit">%</div>
        </div>
        <div class="testArea2">
          <div class="testName">Elapsed</div>
          <div id="statElapsed" class="meterText">00:00</div>
          <div class="unit"></div>
        </div>
      </div>
    </div>

    <div id="chartContainer">
      <canvas id="pingChart"></canvas>
    </div>

    <div id="optionalControls">
      <label>
        Alert threshold:
        <input
          type="range"
          id="alertThreshold"
          min="0"
          max="500"
          step="10"
          value="0"
          oninput="updateThreshold(this.value)"
        />
        <span id="thresholdValue">Off</span>
      </label>
      <button id="downloadCsvBtn" onclick="downloadCsv()">Download CSV</button>
    </div>

    <div class="footer">
      <a href="https://github.com/librespeed/speedtest">Source code</a>
    </div>

    <script type="text/javascript">
      function I(i) {
        return document.getElementById(i);
      }

      // Server configuration (same pattern as index.html)
      // Set this to a different URL to load the server list from another location.
      var SPEEDTEST_SERVERS = "server-list.json";

      // State
      var worker = null;
      var updater = null;
      var running = false;
      var allPingData = []; // full dataset for chart and CSV
      var latestData = null;
      var alertThresholdMs = 0;
      var lastBeepTime = 0;
      var audioCtx = null;
      var selectedServer = null;

      // Dark mode detection for canvas colors
      var isDark = window.matchMedia && window.matchMedia("(prefers-color-scheme: dark)").matches;
      try {
        window.matchMedia("(prefers-color-scheme: dark)").addEventListener("change", function (e) {
          isDark = e.matches;
        });
      } catch (e) {}

      // Chart constants
      var VISIBLE_SECONDS = 60;
      var CHART_PADDING_LEFT = 50;
      var CHART_PADDING_RIGHT = 15;
      var CHART_PADDING_TOP = 15;
      var CHART_PADDING_BOTTOM = 30;

      function joinServerUrl(server, path) {
        if (!server) return path;
        if (!path) return server;
        if (server.charAt(server.length - 1) === "/" || path.charAt(0) === "/") return server + path;
        return server + "/" + path;
      }

      // Load server list dynamically (Docker exposes server-list.json; older setups may expose servers.json)
      function loadServers(callback) {
        if (Array.isArray(SPEEDTEST_SERVERS)) {
          callback();
          return;
        }

        var serverListUrl = typeof SPEEDTEST_SERVERS === "string" ? SPEEDTEST_SERVERS : "";
        if (!serverListUrl) {
          SPEEDTEST_SERVERS = [];
          callback();
          return;
        }

        var xhr = new XMLHttpRequest();
        xhr.onload = function () {
          var loadedServers = null;
          try {
            var servers = JSON.parse(xhr.responseText);
            if (Array.isArray(servers)) {
              loadedServers = servers;
            }
          } catch (e) {}

          if (loadedServers !== null) {
            SPEEDTEST_SERVERS = loadedServers;
            callback();
          } else if (!xhr._fallbackTried) {
            xhr._fallbackTried = true;
            xhr.open("GET", "servers.json?r=" + Math.random());
            xhr.send();
          } else {
            SPEEDTEST_SERVERS = [];
            callback();
          }
        };
        xhr.onerror = function () {
          if (xhr._fallbackTried) {
            SPEEDTEST_SERVERS = [];
            callback();
          } else {
            xhr._fallbackTried = true;
            xhr.open("GET", "servers.json?r=" + Math.random());
            xhr.send();
          }
        };
        xhr.open("GET", serverListUrl + (serverListUrl.match(/\?/) ? "&" : "?") + "r=" + Math.random());
        try {
          xhr.timeout = 2000;
          xhr.ontimeout = xhr.onerror;
        } catch (e) {}
        xhr.send();
      }

      // Server initialization
      function initServers() {
        if (SPEEDTEST_SERVERS.length === 0) {
          I("serverArea").style.display = "none";
        } else {
          I("serverArea").style.display = "";
          // ping servers to find best one
          var completed = 0;
          var best = null;
          for (var i = 0; i < SPEEDTEST_SERVERS.length; i++) {
            (function (idx) {
              pingServer(SPEEDTEST_SERVERS[idx], function (server, rtt) {
                SPEEDTEST_SERVERS[idx].pingT = rtt;
                if (rtt > 0 && (best === null || rtt < best.pingT)) best = SPEEDTEST_SERVERS[idx];
                completed++;
                if (completed === SPEEDTEST_SERVERS.length) {
                  // populate dropdown
                  for (var j = 0; j < SPEEDTEST_SERVERS.length; j++) {
                    if (SPEEDTEST_SERVERS[j].pingT <= 0) continue;
                    var opt = document.createElement("option");
                    opt.value = j;
                    opt.textContent = SPEEDTEST_SERVERS[j].name;
                    if (SPEEDTEST_SERVERS[j] === best) opt.selected = true;
                    I("server").appendChild(opt);
                  }
                  selectedServer = best;
                }
              });
            })(i);
          }
        }
      }

      function pingServer(server, callback) {
        var baseUrl = joinServerUrl(server.server, server.pingURL);
        var url = baseUrl + (baseUrl.match(/\?/) ? "&" : "?") + "cors=true&r=" + Math.random();
        var xhr = new XMLHttpRequest();
        var t = new Date().getTime();
        xhr.onload = function () {
          callback(server, new Date().getTime() - t);
        };
        xhr.onerror = function () {
          callback(server, -1);
        };
        xhr.open("GET", url);
        try {
          xhr.timeout = 2000;
          xhr.ontimeout = xhr.onerror;
        } catch (e) {}
        xhr.send();
      }

      function onServerChange(idx) {
        selectedServer = SPEEDTEST_SERVERS[idx];
      }

      // Start/Stop
      function startStop() {
        if (running) {
          // abort
          if (worker) worker.postMessage("abort");
          stopTest();
        } else {
          startTest();
        }
      }

      function startTest() {
        allPingData = [];
        latestData = null;
        resetUI();

        running = true;
        I("startBtn").className = "running";
        I("durationSelect").disabled = true;
        I("targetSelect").disabled = true;
        I("server").disabled = true;

        var externalTarget = I("targetSelect").value;
        var workerSettings = {
          duration: parseInt(I("durationSelect").value),
          ping_allowPerformanceApi: true,
          url_ping_external: externalTarget
        };

        if (!externalTarget && selectedServer) {
          workerSettings.url_ping = joinServerUrl(selectedServer.server, selectedServer.pingURL);
          workerSettings.mpot = true;
        }

        var currentWorker = new Worker("stability_worker.js?r=" + Math.random());
        worker = currentWorker;
        worker.onmessage = function (e) {
          if (worker !== currentWorker) return;
          var data = JSON.parse(e.data);
          latestData = data;

          // accumulate ping data
          if (data.pingData && data.pingData.length > 0) {
            for (var i = 0; i < data.pingData.length; i++) {
              allPingData.push(data.pingData[i]);
            }
          }

          // check alert threshold
          if (alertThresholdMs > 0 && data.currentPing > alertThresholdMs) {
            playBeep();
          }

          if (data.testState >= 4) {
            stopTest();
          }
        };
        updater = setInterval(function () {
          if (worker) worker.postMessage("status");
        }, 200);
        worker.postMessage("start " + JSON.stringify(workerSettings));
      }

      function stopTest() {
        running = false;
        I("startBtn").className = "";
        I("durationSelect").disabled = false;
        I("targetSelect").disabled = false;
        I("server").disabled = false;
        if (updater) {
          clearInterval(updater);
          updater = null;
        }
        // request final status
        if (worker) {
          var stoppedWorker = worker;
          stoppedWorker.postMessage("status");
          setTimeout(function () {
            try {
              stoppedWorker.terminate();
            } catch (e) {}
            if (worker === stoppedWorker) {
              worker = null;
            }
          }, 500);
        }
      }

      function resetTest() {
        if (running) {
          if (worker) worker.postMessage("abort");
          stopTest();
        }
        allPingData = [];
        latestData = null;
        resetUI();
        drawChart();
      }

      function resetUI() {
        I("statCurrent").textContent = "";
        I("statAvg").textContent = "";
        I("statMin").textContent = "";
        I("statMax").textContent = "";
        I("statJitter").textContent = "";
        I("statLoss").textContent = "";
        I("statElapsed").textContent = "";
        I("rating").textContent = "--";
        I("rating").className = "none";
      }

      // Format helpers
      function fmt(v) {
        v = Number(v);
        if (isNaN(v) || v <= 0) return "--";
        if (v < 10) return v.toFixed(2);
        if (v < 100) return v.toFixed(1);
        return v.toFixed(0);
      }

      function fmtTime(sec) {
        var m = Math.floor(sec / 60);
        var s = Math.floor(sec % 60);
        return (m < 10 ? "0" : "") + m + ":" + (s < 10 ? "0" : "") + s;
      }

      // Rating calculation
      function getRating(avg, jit, loss) {
        if (avg <= 0) return { text: "--", cls: "none" };
        if (avg < 30 && jit < 5 && loss < 0.5) return { text: "Great", cls: "great" };
        if (avg < 60 && jit < 15 && loss < 2) return { text: "Good", cls: "good" };
        if (avg < 100 && jit < 30 && loss < 5) return { text: "Poor", cls: "poor" };
        return { text: "Bad", cls: "bad" };
      }

      // UI update loop
      function updateUI() {
        if (!latestData) return;
        var d = latestData;
        I("statCurrent").textContent = fmt(d.currentPing);
        I("statAvg").textContent = fmt(d.avgPing);
        I("statMin").textContent = d.minPing > 0 ? fmt(d.minPing) : "--";
        I("statMax").textContent = fmt(d.maxPing);
        I("statJitter").textContent = fmt(d.jitter);
        I("statLoss").textContent = d.totalSamples > 0 ? d.packetLoss.toFixed(1) : "--";
        I("statElapsed").textContent = fmtTime(d.elapsed);

        var r = getRating(d.avgPing, d.jitter, d.packetLoss);
        I("rating").textContent = r.text;
        I("rating").className = r.cls;
      }

      // Canvas chart rendering
      function drawChart() {
        var canvas = I("pingChart");
        var ctx = canvas.getContext("2d");
        var dp = window.devicePixelRatio || 1;
        var cw = canvas.clientWidth * dp;
        var ch = canvas.clientHeight * dp;
        if (canvas.width !== cw || canvas.height !== ch) {
          canvas.width = cw;
          canvas.height = ch;
        }
        ctx.clearRect(0, 0, cw, ch);

        var padL = CHART_PADDING_LEFT * dp;
        var padR = CHART_PADDING_RIGHT * dp;
        var padT = CHART_PADDING_TOP * dp;
        var padB = CHART_PADDING_BOTTOM * dp;
        var plotW = cw - padL - padR;
        var plotH = ch - padT - padB;

        // colors based on theme
        var lineColor = isDark ? "#9090FF" : "#6060AA";
        var fillColor = isDark ? "rgba(144,144,255,0.15)" : "rgba(96,96,170,0.15)";
        var gridColor = isDark ? "#404040" : "#E0E0E0";
        var textColor = isDark ? "#A0A0A0" : "#808080";
        var lostColor = "#e74c3c";
        var thresholdColor = "rgba(231,76,60,0.6)";

        // determine visible time window
        var data = allPingData;
        var maxTime = 0;
        if (data.length > 0) maxTime = data[data.length - 1].t;
        var timeStart, timeEnd;
        if (maxTime <= VISIBLE_SECONDS) {
          timeStart = 0;
          timeEnd = Math.max(VISIBLE_SECONDS, maxTime);
        } else {
          timeEnd = maxTime;
          timeStart = maxTime - VISIBLE_SECONDS;
        }

        // binary search to find first visible data point
        var visStart = 0;
        var lo = 0,
          hi = data.length - 1;
        while (lo <= hi) {
          var mid = (lo + hi) >> 1;
          if (data[mid].t < timeStart) lo = mid + 1;
          else hi = mid - 1;
        }
        visStart = lo;

        // determine Y-axis scale from visible data only
        var yMax = 50; // minimum 50ms scale
        for (var i = visStart; i < data.length && data[i].t <= timeEnd; i++) {
          if (!data[i].lost && data[i].ping > yMax) yMax = data[i].ping;
        }
        yMax = Math.ceil((yMax * 1.2) / 10) * 10; // round up to nearest 10 with 20% headroom

        var fontSize = 11 * dp;
        ctx.font = fontSize + "px sans-serif";
        ctx.textBaseline = "middle";

        // grid lines - horizontal
        var ySteps = getYSteps(yMax);
        ctx.strokeStyle = gridColor;
        ctx.lineWidth = dp;
        ctx.fillStyle = textColor;
        ctx.textAlign = "right";
        for (var s = 0; s < ySteps.length; s++) {
          var yVal = ySteps[s];
          if (yVal > yMax) continue;
          var y = padT + plotH - (yVal / yMax) * plotH;
          ctx.beginPath();
          ctx.moveTo(padL, y);
          ctx.lineTo(padL + plotW, y);
          ctx.stroke();
          ctx.fillText(yVal + "", padL - 5 * dp, y);
        }

        // grid lines - vertical (time ticks)
        ctx.textAlign = "center";
        ctx.textBaseline = "top";
        var timeSpan = timeEnd - timeStart;
        var tickInterval = timeSpan <= 60 ? 10 : timeSpan <= 120 ? 15 : 30;
        var firstTick = Math.ceil(timeStart / tickInterval) * tickInterval;
        for (var t = firstTick; t <= timeEnd; t += tickInterval) {
          var x = padL + ((t - timeStart) / timeSpan) * plotW;
          ctx.beginPath();
          ctx.strokeStyle = gridColor;
          ctx.moveTo(x, padT);
          ctx.lineTo(x, padT + plotH);
          ctx.stroke();
          ctx.fillStyle = textColor;
          ctx.fillText(fmtTime(t), x, padT + plotH + 4 * dp);
        }

        // axis labels
        ctx.fillStyle = textColor;
        ctx.textAlign = "right";
        ctx.textBaseline = "top";
        ctx.fillText("ms", padL - 5 * dp, padT - 2 * dp);

        // plot border
        ctx.strokeStyle = gridColor;
        ctx.lineWidth = dp;
        ctx.strokeRect(padL, padT, plotW, plotH);

        // alert threshold line
        if (alertThresholdMs > 0 && alertThresholdMs <= yMax) {
          var threshY = padT + plotH - (alertThresholdMs / yMax) * plotH;
          ctx.save();
          ctx.setLineDash([6 * dp, 4 * dp]);
          ctx.strokeStyle = thresholdColor;
          ctx.lineWidth = 1.5 * dp;
          ctx.beginPath();
          ctx.moveTo(padL, threshY);
          ctx.lineTo(padL + plotW, threshY);
          ctx.stroke();
          ctx.restore();
        }

        if (data.length < 2) return;

        // filter visible data (using binary search start index)
        var visible = [];
        for (var i = visStart; i < data.length && data[i].t <= timeEnd; i++) {
          visible.push(data[i]);
        }
        if (visible.length < 1) return;

        // draw filled area
        ctx.beginPath();
        var started = false;
        for (var i = 0; i < visible.length; i++) {
          if (visible[i].lost) continue;
          var px = padL + ((visible[i].t - timeStart) / timeSpan) * plotW;
          var py = padT + plotH - (visible[i].ping / yMax) * plotH;
          if (!started) {
            ctx.moveTo(px, padT + plotH);
            ctx.lineTo(px, py);
            started = true;
          } else {
            ctx.lineTo(px, py);
          }
        }
        // close the fill path
        if (started) {
          // find last non-lost point
          for (var i = visible.length - 1; i >= 0; i--) {
            if (!visible[i].lost) {
              var px = padL + ((visible[i].t - timeStart) / timeSpan) * plotW;
              ctx.lineTo(px, padT + plotH);
              break;
            }
          }
          ctx.closePath();
          ctx.fillStyle = fillColor;
          ctx.fill();
        }

        // draw line
        ctx.beginPath();
        started = false;
        for (var i = 0; i < visible.length; i++) {
          if (visible[i].lost) {
            started = false;
            continue;
          }
          var px = padL + ((visible[i].t - timeStart) / timeSpan) * plotW;
          var py = padT + plotH - (visible[i].ping / yMax) * plotH;
          if (!started) {
            ctx.moveTo(px, py);
            started = true;
          } else {
            ctx.lineTo(px, py);
          }
        }
        ctx.strokeStyle = lineColor;
        ctx.lineWidth = 2 * dp;
        ctx.lineJoin = "round";
        ctx.stroke();

        // draw failed request markers
        for (var i = 0; i < visible.length; i++) {
          if (!visible[i].lost) continue;
          var px = padL + ((visible[i].t - timeStart) / timeSpan) * plotW;
          ctx.beginPath();
          ctx.arc(px, padT + plotH - 10 * dp, 3 * dp, 0, Math.PI * 2);
          ctx.fillStyle = lostColor;
          ctx.fill();
        }
      }

      function getYSteps(yMax) {
        // generate sensible Y-axis grid steps
        if (yMax <= 50) return [10, 20, 30, 40, 50];
        if (yMax <= 100) return [20, 40, 60, 80, 100];
        if (yMax <= 200) return [50, 100, 150, 200];
        if (yMax <= 500) return [100, 200, 300, 400, 500];
        // for very high values
        var step = Math.ceil(yMax / 5 / 100) * 100;
        var steps = [];
        for (var v = step; v <= yMax; v += step) steps.push(v);
        return steps;
      }

      // Animation frame loop
      window.requestAnimationFrame =
        window.requestAnimationFrame ||
        window.webkitRequestAnimationFrame ||
        window.mozRequestAnimationFrame ||
        window.msRequestAnimationFrame ||
        function (callback) {
          setTimeout(callback, 1000 / 60);
        };
      function frame() {
        requestAnimationFrame(frame);
        updateUI();
        drawChart();
      }
      frame();

      // Alert threshold
      function updateThreshold(val) {
        alertThresholdMs = parseInt(val);
        I("thresholdValue").textContent = alertThresholdMs > 0 ? alertThresholdMs + " ms" : "Off";
      }

      function playBeep() {
        var now = new Date().getTime();
        if (now - lastBeepTime < 1000) return; // debounce 1s
        lastBeepTime = now;
        try {
          if (!audioCtx) audioCtx = new (window.AudioContext || window.webkitAudioContext)();
          var osc = audioCtx.createOscillator();
          var gain = audioCtx.createGain();
          osc.frequency.value = 800;
          gain.gain.value = 0.3;
          osc.connect(gain);
          gain.connect(audioCtx.destination);
          osc.start();
          osc.stop(audioCtx.currentTime + 0.1);
        } catch (e) {}
      }

      // CSV download
      function downloadCsv() {
        if (allPingData.length === 0) return;
        var csv = "elapsed_s,ping_ms,failed\n";
        for (var i = 0; i < allPingData.length; i++) {
          var d = allPingData[i];
          csv += d.t.toFixed(3) + "," + d.ping.toFixed(2) + "," + (d.lost ? "1" : "0") + "\n";
        }
        var blob = new Blob([csv], { type: "text/csv" });
        var url = URL.createObjectURL(blob);
        var a = document.createElement("a");
        a.href = url;
        a.download = "stability_test_" + new Date().toISOString().slice(0, 19).replace(/:/g, "-") + ".csv";
        document.body.appendChild(a);
        a.click();
        document.body.removeChild(a);
        URL.revokeObjectURL(url);
      }

      // Init — load server list first (async), then initialize UI
      loadServers(function () {
        initServers();
        drawChart();
      });
    </script>
  </body>
</html>