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// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
/**
* @fileoverview Implements the setFocus function.
*/
goog.provide('cvox.Focuser');
goog.require('cvox.ChromeVoxEventSuspender');
goog.require('cvox.DomUtil');
/**
* Sets the browser focus to the targetNode or its closest ancestor that is
* focusable.
*
* @param {Node} targetNode The node to move the browser focus to.
* @param {boolean=} opt_focusDescendants Whether or not we check descendants
* of the target node to see if they are focusable. If true, sets focus on the
* first focusable descendant. If false, only sets focus on the targetNode or
* its closest ancestor. Default is false.
*/
cvox.Focuser.setFocus = function(targetNode, opt_focusDescendants) {
// Save the selection because Chrome will lose it if there's a focus or blur.
var sel = window.getSelection();
var range;
if (sel.rangeCount > 0) {
range = sel.getRangeAt(0);
}
// Blur the currently-focused element if the target node is not a descendant.
if (document.activeElement &&
!cvox.DomUtil.isDescendantOfNode(targetNode, document.activeElement)) {
document.activeElement.blur();
}
// Video elements should always be focusable.
if (targetNode && (targetNode.constructor == HTMLVideoElement)) {
if (!cvox.DomUtil.isFocusable(targetNode)) {
targetNode.setAttribute('tabIndex', 0);
}
}
if (opt_focusDescendants && !cvox.DomUtil.isFocusable(targetNode)) {
var focusableDescendant = cvox.DomUtil.findFocusableDescendant(targetNode);
if (focusableDescendant) {
targetNode = focusableDescendant;
}
} else {
// Search up the parent chain until a focusable node is found.
while (targetNode && !cvox.DomUtil.isFocusable(targetNode)) {
targetNode = targetNode.parentNode;
}
}
// If we found something focusable, focus it - otherwise, blur it.
if (cvox.DomUtil.isFocusable(targetNode)) {
// Don't let the instance of ChromeVox in the parent focus iframe children
// - instead, let the instance of ChromeVox in the iframe focus itself to
// avoid getting trapped in iframes that have no ChromeVox in them.
// This self focusing is performed by calling window.focus() in
// cvox.NavigationManager.prototype.addInterframeListener_
if (targetNode.tagName != 'IFRAME') {
// setTimeout must be used because there's a bug (in Chrome, I think)
// with .focus() which causes the page to be redrawn incorrectly if
// not in setTimeout.
if (cvox.ChromeVoxEventSuspender.areEventsSuspended()) {
if (cvox.Focuser.shouldEnterSuspendEvents_(targetNode)) {
cvox.ChromeVoxEventSuspender.enterSuspendEvents();
}
window.setTimeout(function() {
targetNode.focus();
cvox.ChromeVoxEventSuspender.exitSuspendEvents();
}, 0);
}
else {
window.setTimeout(function() {
targetNode.focus();
}, 0);
}
}
} else if (document.activeElement &&
document.activeElement.tagName != 'BODY') {
document.activeElement.blur();
}
// Restore the selection, unless the focused item is a text box.
if (cvox.DomUtil.isInputTypeText(targetNode)) {
targetNode.select();
} else if (range) {
sel.removeAllRanges();
sel.addRange(range);
}
};
/**
* Rules for whether or not enterSuspendEvents should be called.
* In general, we should not enterSuspendEvents if the targetNode will get some
* special handlers attached when a focus event is received for it; otherwise,
* the special handlers will not get attached.
*
* @param {Node} targetNode The node that is being focused.
* @return {boolean} True if enterSuspendEvents should be called.
*/
cvox.Focuser.shouldEnterSuspendEvents_ = function(targetNode){
if (targetNode.constructor && targetNode.constructor == HTMLVideoElement) {
return false;
}
if (targetNode.hasAttribute) {
switch (targetNode.getAttribute('type')) {
case 'time':
case 'date':
case 'week':
case 'month':
return false;
}
}
return true;
};
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