/**
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* Copyright 2013-2015, Facebook, Inc.
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* All rights reserved.
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*
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* This source code is licensed under the BSD-style license found in the
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* LICENSE file in the root directory of this source tree. An additional grant
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* of patent rights can be found in the PATENTS file in the same directory.
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*
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* @providesModule isEventSupported
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*/
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'use strict';
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var ExecutionEnvironment = require('./ExecutionEnvironment');
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var useHasFeature;
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if (ExecutionEnvironment.canUseDOM) {
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useHasFeature =
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document.implementation &&
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document.implementation.hasFeature &&
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// always returns true in newer browsers as per the standard.
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// @see http://dom.spec.whatwg.org/#dom-domimplementation-hasfeature
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document.implementation.hasFeature('', '') !== true;
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}
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/**
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* Checks if an event is supported in the current execution environment.
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*
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* NOTE: This will not work correctly for non-generic events such as `change`,
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* `reset`, `load`, `error`, and `select`.
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*
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* Borrows from Modernizr.
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*
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* @param {string} eventNameSuffix Event name, e.g. "click".
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* @param {?boolean} capture Check if the capture phase is supported.
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* @return {boolean} True if the event is supported.
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* @internal
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* @license Modernizr 3.0.0pre (Custom Build) | MIT
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*/
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function isEventSupported(eventNameSuffix, capture) {
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if (!ExecutionEnvironment.canUseDOM ||
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capture && !('addEventListener' in document)) {
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return false;
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}
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var eventName = 'on' + eventNameSuffix;
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var isSupported = eventName in document;
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if (!isSupported) {
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var element = document.createElement('div');
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element.setAttribute(eventName, 'return;');
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isSupported = typeof element[eventName] === 'function';
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}
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if (!isSupported && useHasFeature && eventNameSuffix === 'wheel') {
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// This is the only way to test support for the `wheel` event in IE9+.
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isSupported = document.implementation.hasFeature('Events.wheel', '3.0');
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}
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return isSupported;
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}
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module.exports = isEventSupported;
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