<!DOCTYPE html>
<meta charset="utf-8">
<html>
<head>
  <title>Alloc memory</title>
  <meta http-equiv="Cache-Control" content="no-store" />
  <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>
</head>
<body>
<div id="display">
  Allocating memory...
</div>
<script>
  function alloc(sizeMB) {
    var FLOAT64_BYTES = 8;
    var MB = 1024 * 1024;
    var count = sizeMB* MB / FLOAT64_BYTES;
    // Random content is uncompressable.
    var content = new Float64Array(count);
    for (var i = 0; i < content.length; i++) {
      content[i] = Math.random();
    }
    return content;
    document.out = arr;
  }
  $(document).ready(function() {
    var url = new URL(window.location.href);
    var allocMB = parseInt(url.searchParams.get("alloc"));
    if (isNaN(allocMB))
      allocMB = 800;

    var startTime = new Date();
    // Assigns the content to docuement to avoid optimization of unused data.
    document.out = alloc(allocMB);
    var ellapse = (new Date() - startTime) / 1000;
    $("#display").text("Allocating " + allocMB + " MB takes " + ellapse + " seconds");
  });
</script>
</body>
</html>