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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 Character counter widget implementation.
*
* @author eae@google.com (Emil A Eklund)
* @see ../demos/charcounter.html
*/
goog.provide('goog.ui.CharCounter');
goog.provide('goog.ui.CharCounter.Display');
goog.require('goog.dom');
goog.require('goog.events');
goog.require('goog.events.EventTarget');
goog.require('goog.events.InputHandler');
/**
* CharCounter widget. Counts the number of characters in a input field or a
* text box and displays the number of additional characters that may be
* entered before the maximum length is reached.
*
* @extends {goog.events.EventTarget}
* @param {HTMLInputElement|HTMLTextAreaElement} elInput Input or text area
* element to count the number of characters in.
* @param {Element} elCount HTML element to display the remaining number of
* characters in. You can pass in null for this if you don't want to expose
* the number of chars remaining.
* @param {number} maxLength The maximum length.
* @param {goog.ui.CharCounter.Display=} opt_displayMode Display mode for this
* char counter. Defaults to {@link goog.ui.CharCounter.Display.REMAINING}.
* @constructor
* @final
*/
goog.ui.CharCounter = function(elInput, elCount, maxLength, opt_displayMode) {
goog.events.EventTarget.call(this);
/**
* Input or text area element to count the number of characters in.
* @type {HTMLInputElement|HTMLTextAreaElement}
* @private
*/
this.elInput_ = elInput;
/**
* HTML element to display the remaining number of characters in.
* @type {Element}
* @private
*/
this.elCount_ = elCount;
/**
* The maximum length.
* @type {number}
* @private
*/
this.maxLength_ = maxLength;
/**
* The display mode for this char counter.
* @type {!goog.ui.CharCounter.Display}
* @private
*/
this.display_ = opt_displayMode || goog.ui.CharCounter.Display.REMAINING;
elInput.removeAttribute('maxlength');
/**
* The input handler that provides the input event.
* @type {goog.events.InputHandler}
* @private
*/
this.inputHandler_ = new goog.events.InputHandler(elInput);
goog.events.listen(
this.inputHandler_, goog.events.InputHandler.EventType.INPUT,
this.onChange_, false, this);
this.checkLength();
};
goog.inherits(goog.ui.CharCounter, goog.events.EventTarget);
/**
* Display mode for the char counter.
* @enum {number}
*/
goog.ui.CharCounter.Display = {
/** Widget displays the number of characters remaining (the default). */
REMAINING: 0,
/** Widget displays the number of characters entered. */
INCREMENTAL: 1
};
/**
* Sets the maximum length.
*
* @param {number} maxLength The maximum length.
*/
goog.ui.CharCounter.prototype.setMaxLength = function(maxLength) {
this.maxLength_ = maxLength;
this.checkLength();
};
/**
* Returns the maximum length.
*
* @return {number} The maximum length.
*/
goog.ui.CharCounter.prototype.getMaxLength = function() {
return this.maxLength_;
};
/**
* Sets the display mode.
*
* @param {!goog.ui.CharCounter.Display} displayMode The display mode.
*/
goog.ui.CharCounter.prototype.setDisplayMode = function(displayMode) {
this.display_ = displayMode;
this.checkLength();
};
/**
* Returns the display mode.
*
* @return {!goog.ui.CharCounter.Display} The display mode.
*/
goog.ui.CharCounter.prototype.getDisplayMode = function() {
return this.display_;
};
/**
* Change event handler for input field.
*
* @param {goog.events.BrowserEvent} event Change event.
* @private
*/
goog.ui.CharCounter.prototype.onChange_ = function(event) {
this.checkLength();
};
/**
* Checks length of text in input field and updates the counter. Truncates text
* if the maximum lengths is exceeded.
*/
goog.ui.CharCounter.prototype.checkLength = function() {
var count = this.elInput_.value.length;
// There's no maxlength property for textareas so instead we truncate the
// text if it gets too long. It's also used to truncate the text in a input
// field if the maximum length is changed.
if (count > this.maxLength_) {
var scrollTop = this.elInput_.scrollTop;
var scrollLeft = this.elInput_.scrollLeft;
this.elInput_.value = this.elInput_.value.substring(0, this.maxLength_);
count = this.maxLength_;
this.elInput_.scrollTop = scrollTop;
this.elInput_.scrollLeft = scrollLeft;
}
if (this.elCount_) {
var incremental = this.display_ == goog.ui.CharCounter.Display.INCREMENTAL;
goog.dom.setTextContent(
this.elCount_, String(incremental ? count : this.maxLength_ - count));
}
};
/** @override */
goog.ui.CharCounter.prototype.disposeInternal = function() {
goog.ui.CharCounter.superClass_.disposeInternal.call(this);
delete this.elInput_;
this.inputHandler_.dispose();
this.inputHandler_ = null;
};
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