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// Copyright 2006 The Closure Library Authors. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS-IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
/**
* @fileoverview An object that encapsulates text changed events for textareas
* and input element of type text and password. The event occurs after the value
* has been changed. The event does not occur if value was changed
* programmatically.<br>
* <br>
* Note: this does not guarantee the correctness of {@code keyCode} or
* {@code charCode}, or attempt to unify them across browsers. See
* {@code goog.events.KeyHandler} for that functionality.<br>
* <br>
* Known issues:
* <ul>
* <li>Does not trigger for drop events on Opera due to browser bug.
* <li>IE doesn't have native support for input event. WebKit before version 531
* doesn't have support for textareas. For those browsers an emulation mode
* based on key, clipboard and drop events is used. Thus this event won't
* trigger in emulation mode if text was modified by context menu commands
* such as 'Undo' and 'Delete'.
* </ul>
* @author arv@google.com (Erik Arvidsson)
* @see ../demos/inputhandler.html
*/
goog.provide('goog.events.InputHandler');
goog.provide('goog.events.InputHandler.EventType');
goog.require('goog.Timer');
goog.require('goog.dom');
goog.require('goog.events');
goog.require('goog.events.BrowserEvent');
goog.require('goog.events.EventHandler');
goog.require('goog.events.EventTarget');
goog.require('goog.events.KeyCodes');
goog.require('goog.userAgent');
/**
* This event handler will dispatch events when the user types into a text
* input, password input or a textarea
* @param {Element} element The element that you want to listen for input
* events on.
* @constructor
* @extends {goog.events.EventTarget}
*/
goog.events.InputHandler = function(element) {
goog.events.EventTarget.call(this);
/**
* The element that you want to listen for input events on.
* @type {Element}
* @private
*/
this.element_ = element;
/**
* Whether input event is emulated.
* IE doesn't support input events. We could use property change events but
* they are broken in many ways:
* - Fire even if value was changed programmatically.
* - Aren't always delivered. For example, if you change value or even width
* of input programmatically, next value change made by user won't fire an
* event.
* WebKit before version 531 did not support input events for textareas.
* @type {boolean}
* @private
*/
this.inputEventEmulation_ =
goog.userAgent.IE ||
(goog.userAgent.WEBKIT && !goog.userAgent.isVersion('531') &&
element.tagName == 'TEXTAREA');
/**
* @type {goog.events.EventHandler}
* @private
*/
this.eventHandler_ = new goog.events.EventHandler(this);
this.eventHandler_.listen(
this.element_,
this.inputEventEmulation_ ? ['keydown', 'paste', 'cut', 'drop'] : 'input',
this);
};
goog.inherits(goog.events.InputHandler, goog.events.EventTarget);
/**
* Enum type for the events fired by the input handler
* @enum {string}
*/
goog.events.InputHandler.EventType = {
INPUT: 'input'
};
/**
* Id of a timer used to postpone firing input event in emulation mode.
* @type {?number}
* @private
*/
goog.events.InputHandler.prototype.timer_ = null;
/**
* This handles the underlying events and dispatches a new event as needed.
* @param {goog.events.BrowserEvent} e The underlying browser event.
*/
goog.events.InputHandler.prototype.handleEvent = function(e) {
if (this.inputEventEmulation_) {
// Filter out key events that don't modify text.
if (e.type == 'keydown' &&
!goog.events.KeyCodes.isTextModifyingKeyEvent(e)) {
return;
}
// It is still possible that pressed key won't modify the value of an
// element. Storing old value will help us to detect modification but is
// also a little bit dangerous. If value is changed programmatically in
// another key down handler, we will detect it as user-initiated change.
var valueBeforeKey = e.type == 'keydown' ? this.element_.value : null;
// In IE on XP, IME the element's value has already changed when we get
// keydown events when the user is using an IME. In this case, we can't
// check the current value normally, so we assume that it's a modifying key
// event. This means that ENTER when used to commit will fire a spurious
// input event, but it's better to have a false positive than let some input
// slip through the cracks.
if (goog.userAgent.IE && e.keyCode == goog.events.KeyCodes.WIN_IME) {
valueBeforeKey = null;
}
// Create an input event now, because when we fire it on timer, the
// underlying event will already be disposed.
var inputEvent = this.createInputEvent_(e);
// Since key down, paste, cut and drop events are fired before actual value
// of the element has changed, we need to postpone dispatching input event
// until value is updated.
this.cancelTimerIfSet_();
this.timer_ = goog.Timer.callOnce(function() {
this.timer_ = null;
if (this.element_.value != valueBeforeKey) {
this.dispatchEvent(inputEvent);
}
}, 0, this);
} else {
// Unlike other browsers, Opera fires an extra input event when an element
// is blurred after the user has input into it. Since Opera doesn't fire
// input event on drop, it's enough to check whether element still has focus
// to suppress bogus notification.
if (!goog.userAgent.OPERA || this.element_ ==
goog.dom.getOwnerDocument(this.element_).activeElement) {
this.dispatchEvent(this.createInputEvent_(e));
}
}
};
/**
* Cancels timer if it is set, does nothing otherwise.
* @private
*/
goog.events.InputHandler.prototype.cancelTimerIfSet_ = function() {
if (this.timer_ != null) {
goog.Timer.clear(this.timer_);
this.timer_ = null;
}
};
/**
* Creates an input event from the browser event.
* @param {goog.events.BrowserEvent} be A browser event.
* @return {goog.events.BrowserEvent} An input event.
* @private
*/
goog.events.InputHandler.prototype.createInputEvent_ = function(be) {
var e = new goog.events.BrowserEvent(be.getBrowserEvent());
e.type = goog.events.InputHandler.EventType.INPUT;
return e;
};
/** @override */
goog.events.InputHandler.prototype.disposeInternal = function() {
goog.events.InputHandler.superClass_.disposeInternal.call(this);
this.eventHandler_.dispose();
this.cancelTimerIfSet_();
delete this.element_;
};
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