2017-04-15 01:32:37 +03:00
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<!doctype html>
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<html>
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<body>
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<p>
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There are currently <span id="totalInnerHandlers">0</span> beforeunload handlers registered in this frame.
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</p>
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<p>
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There are currently <span id="totalOuterHandlers">0</span> beforeunload handlers registered on my subframe.
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</p>
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<iframe src="about:blank" id="subframe"></iframe>
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<script>
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this.BeforeUnloader = {
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_innerEventHandlers: [],
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_outerEventHandlers: [],
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get $totalInner() {
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delete this.$totalInner;
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return this.$totalInner = document.getElementById("totalInnerHandlers");
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},
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get $totalOuter() {
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delete this.$totalOuter;
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return this.$totalOuter = document.getElementById("totalOuterHandlers");
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},
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get $subframe() {
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delete this.$subframe;
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return this.$subframe = document.getElementById("subframe");
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},
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pushInner(howMany) {
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for (let i = 0; i < howMany; ++i) {
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let func = () => {};
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this._innerEventHandlers.push(func);
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addEventListener("beforeunload", func);
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}
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this.$totalInner.textContent = this._innerEventHandlers.length;
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},
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popInner(howMany) {
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for (let i = 0; i < howMany; ++i) {
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let func = this._innerEventHandlers.pop();
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if (func) {
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removeEventListener("beforeunload", func);
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}
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}
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this.$totalInner.textContent = this._innerEventHandlers.length;
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},
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pushOuter(howMany) {
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if (!this.$subframe.parentNode) {
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throw new Error("Subframe I'm holding a reference to detached!");
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}
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for (let i = 0; i < howMany; ++i) {
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let func = () => {};
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this._outerEventHandlers.push(func);
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this.$subframe.contentWindow.addEventListener("beforeunload", func);
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}
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this.$totalOuter.textContent = this._outerEventHandlers.length;
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},
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popOuter(howMany) {
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if (!this.$subframe.parentNode) {
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throw new Error("Subframe I'm holding a reference to detached!");
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}
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for (let i = 0; i < howMany; ++i) {
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let func = this._outerEventHandlers.pop();
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if (func) {
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this.$subframe.contentWindow.removeEventListener("beforeunload", func);
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}
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}
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this.$totalOuter.textContent = this._outerEventHandlers.length;
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},
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reset() {
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this.popInner(this._innerEventHandlers.length);
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this.popOuter(this._outerEventHandlers.length);
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2019-01-23 00:26:30 +03:00
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},
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2017-04-15 01:32:37 +03:00
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};
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</script>
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</body>
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</html>
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