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Test Info:
- This WPT test may be referenced by the following Test IDs:
- /html/webappapis/scripting/events/eventhandler-cancellation.html - WPT Dashboard Interop Dashboard
<!doctype html>
<meta charset=utf-8>
<title></title>
<script src=/resources/testharness.js></script>
<script src=/resources/testharnessreport.js></script>
<!-- A window to work with that won't trigger the harness exception detection
when we fire "error" events at it -->
<iframe style="display: none"></iframe>
<script>
test(function() {
var blob = new Blob([""]);
// Most targets disabled for now until
var targets = [ frames[0] /*, document, document.documentElement,
new Worker(URL.createObjectURL(blob) */ ];
// Event constructors also mostly disabled until
var eventCtors = [ /* Event, */ ErrorEvent /*, MouseEvent */ ];
var values = [true, false, "", "abc", {}, 0, 1, -1, null, undefined,
2.5, NaN, Infinity, Symbol.toStringTag ];
// Event types also mostly disabled pending
var eventTypes = [ "error"/*, "click", "load"*/ ];
// Variables that keep track of which subtest we're running.
var curTarget;
var curValue;
var curCtor;
var curType;
function defaultPreventedTester(event) {
var expectedValue;
if (curTarget === frames[0] &&
curCtor === ErrorEvent &&
curValue === true &&
curType == "error") {
expectedValue = true;
} else {
// This will need adjusting once we allow more targets and event
// constructors above!
expectedValue = false;
}
var valueRepr;
if (typeof curValue == "string") {
valueRepr = '"' + curValue + '"';
} else {
valueRepr = String(curValue);
}
test(function() {
assert_equals(event.defaultPrevented, expectedValue);
}, "Returning " + valueRepr +
" from " + String(curTarget) + "'s on" + curType +
" event handler while " + curCtor.name +
" is firing should" +
(expectedValue ? "" : " not") +
" cancel the event");
}
for (curCtor of eventCtors) {
for (curTarget of targets) {
for (curType of eventTypes) {
for (curValue of values) {
// We have to make sure that defaultPreventedTester is added after
// our event handler.
curTarget["on" + curType] = function() { return curValue; }
curTarget.addEventListener(curType, defaultPreventedTester);
var e = new curCtor(curType, { cancelable: true });
curTarget.dispatchEvent(e);
curTarget["on" + curType] = null;
curTarget.removeEventListener(curType, defaultPreventedTester);
}
}
}
}
}, "event handler cancellation behavior");
</script>