blob: f26cfa7b92510b706b556229c2d2608d35b2e804 [file] [log] [blame]
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) {
if (!multiplyFactor) {
if (timerCount == 0)
log("No more timers - UI should be responsive now.");
// 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);
// 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);
<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>