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<html>
<head>
<script>
function log(m) {
document.getElementById("log").innerHTML += m + "<br>";
}
var multiplyFactor = 2; // Create this many timers in every timer callback.
var targetLatency = 10000; // Multiply timers until it takes this much to fire all their callbacks.
var timerCount = 1;
function timerCallback(creationTimestamp) {
--timerCount;
if (!multiplyFactor) {
if (timerCount == 0)
log("No more timers - UI should be responsive now.");
return;
}
// Create more timers. Capture the current time so when callbacks are fired,
// we can check how long it actually took (latency caused by a long timer queue).
var timestamp = new Date().getTime();
for (i = 0; i < multiplyFactor; ++i) {
setTimeout(function() { timerCallback(timestamp); }, 0);
++timerCount;
}
// Once the timer queue gets long enough for the timer firing latency to be over the limit,
// stop multplying them and keep the number of timers constant.
if (multiplyFactor > 1 && new Date().getTime() - creationTimestamp > targetLatency)
multiplyFactor = 1;
}
function runTest() {
log("Freezing UI...");
setTimeout(function() { timerCallback(new Date().getTime()); }, 0);
setTimeout("multiplyFactor = 0; log('Finishing. Started to drain timers.');", 10000);
}
</script>
</head>
<body onload="runTest()">
This test will create enough timers to freeze browser UI. After 10 seconds, it
will start drain the timers so the UI becomes responsive again in a few seconds.
You don't need to kill the browser.<br>If the bug is fixed, there will be no
UI freeze. Refresh the page to repeat the experiment.<br>Try to click at this
button (or browser's menu) while UI is frozen: <button onclick="log('clicked')">Click Me</button> <hr>
<div id="log"></div>
</body>
</html>
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