third_party/WebKit/ManualTests/input-starved-by-timers.html

   1 <html>
   2 <head>
   3 <script>
   4 function log(m) {
   5     document.getElementById("log").innerHTML += m + "<br>";
   6 }
   7
   8 var multiplyFactor = 2;   // Create this many timers in every timer callback.
   9 var targetLatency = 10000; // Multiply timers until it takes this much to fire all their callbacks.
  10 var timerCount = 1;
  11
  12 function timerCallback(creationTimestamp) {
  13     --timerCount;
  14
  15     if (!multiplyFactor) {
  16         if (timerCount == 0)
  17             log("No more timers - UI should be responsive now.");
  18         return;
  19     }
  20
  21     // Create more timers. Capture the current time so when callbacks are fired,
  22     // we can check how long it actually took (latency caused by a long timer queue).
  23     var timestamp = new Date().getTime();
  24     for (i = 0; i < multiplyFactor; ++i) {
  25         setTimeout(function() { timerCallback(timestamp); }, 0);
  26         ++timerCount;
  27     }
  28
  29     // Once the timer queue gets long enough for the timer firing latency to be over the limit,
  30     // stop multplying them and keep the number of timers constant.
  31     if (multiplyFactor > 1 && new Date().getTime() - creationTimestamp > targetLatency)
  32         multiplyFactor = 1;
  33 }
  34
  35 function runTest() {
  36     log("Freezing UI...");
  37     setTimeout(function() { timerCallback(new Date().getTime()); }, 0);
  38     setTimeout("multiplyFactor = 0; log('Finishing. Started to drain timers.');", 10000);
  39 }
  40
  41 </script>
  42 </head>
  43 <body onload="runTest()">
  44 This test will create enough timers to freeze browser UI. After 10 seconds, it
  45 will start drain the timers so the UI becomes responsive again in a few seconds.
  46 You don't need to kill the browser.<br>If the bug is fixed, there will be no
  47 UI freeze. Refresh the page to repeat the experiment.<br>Try to click at this
  48 button (or browser's menu) while UI is frozen: <button onclick="log('clicked')">Click Me</button> <hr>
  49 <div id="log"></div>
  50 </body>
  51 </html>