Andreas Hocevar
88 lines
2.7 KiB
JavaScript
88 lines
2.7 KiB
JavaScript
// Copyright 2011 The Closure Library Authors. All Rights Reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS-IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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/**
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* @fileoverview Helper object used by modal elements to control aria
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* visibility of the rest of the page.
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*/
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goog.provide('goog.ui.ModalAriaVisibilityHelper');
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goog.require('goog.a11y.aria');
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goog.require('goog.a11y.aria.State');
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/**
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* Helper object to control aria visibility of the rest of the page (background)
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* for a given element. Example usage is to restrict screenreader focus to
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* a modal popup while it is visible.
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*
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* WARNING: This will work only if the element is rendered directly in the
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* 'body' element.
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*
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* @param {!Element} element The given element.
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* @param {!goog.dom.DomHelper} domHelper DomHelper for the page.
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* @constructor
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*/
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goog.ui.ModalAriaVisibilityHelper = function(element, domHelper) {
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/**
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* @private {!Element}
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*/
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this.element_ = element;
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/**
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* @private {!goog.dom.DomHelper}
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*/
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this.dom_ = domHelper;
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};
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/**
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* The elements set to aria-hidden when the popup was made visible.
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* @type {Array<!Element>}
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* @private
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*/
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goog.ui.ModalAriaVisibilityHelper.prototype.hiddenElements_;
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/**
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* Sets aria-hidden on the rest of the page to restrict screen reader focus.
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* Top-level elements with an explicit aria-hidden state are not altered.
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* @param {boolean} hide Whether to hide or show the rest of the page.
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*/
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goog.ui.ModalAriaVisibilityHelper.prototype.setBackgroundVisibility = function(
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hide) {
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if (hide) {
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if (!this.hiddenElements_) {
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this.hiddenElements_ = [];
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}
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var topLevelChildren = this.dom_.getChildren(this.dom_.getDocument().body);
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for (var i = 0; i < topLevelChildren.length; i++) {
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var child = topLevelChildren[i];
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if (child != this.element_ &&
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!goog.a11y.aria.getState(child, goog.a11y.aria.State.HIDDEN)) {
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goog.a11y.aria.setState(child, goog.a11y.aria.State.HIDDEN, true);
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this.hiddenElements_.push(child);
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}
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}
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} else if (this.hiddenElements_) {
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for (var i = 0; i < this.hiddenElements_.length; i++) {
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goog.a11y.aria.removeState(
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this.hiddenElements_[i], goog.a11y.aria.State.HIDDEN);
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}
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this.hiddenElements_ = null;
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}
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};
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