459 lines
19 KiB
JavaScript
459 lines
19 KiB
JavaScript
/*
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* The MIT License
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*
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* Copyright (c) 2012 James Allardice
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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// Defines the global Placeholders object along with various utility methods
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(function (global) {
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"use strict";
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// Cross-browser DOM event binding
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function addEventListener(elem, event, fn) {
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if (elem.addEventListener) {
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return elem.addEventListener(event, fn, false);
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}
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if (elem.attachEvent) {
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return elem.attachEvent("on" + event, fn);
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}
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}
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// Check whether an item is in an array (we don't use Array.prototype.indexOf so we don't clobber any existing polyfills - this is a really simple alternative)
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function inArray(arr, item) {
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var i, len;
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for (i = 0, len = arr.length; i < len; i++) {
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if (arr[i] === item) {
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return true;
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}
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}
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return false;
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}
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// Move the caret to the index position specified. Assumes that the element has focus
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function moveCaret(elem, index) {
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var range;
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if (elem.createTextRange) {
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range = elem.createTextRange();
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range.move("character", index);
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range.select();
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} else if (elem.selectionStart) {
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elem.focus();
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elem.setSelectionRange(index, index);
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}
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}
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// Attempt to change the type property of an input element
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function changeType(elem, type) {
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try {
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elem.type = type;
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return true;
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} catch (e) {
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// You can't change input type in IE8 and below
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return false;
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}
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}
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// Expose public methods
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global.Placeholders = {
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Utils: {
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addEventListener: addEventListener,
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inArray: inArray,
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moveCaret: moveCaret,
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changeType: changeType
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}
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};
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}(this));
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(function (global) {
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"use strict";
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var validTypes = [
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"text",
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"search",
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"url",
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"tel",
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"email",
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"password",
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"number",
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"textarea"
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],
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// The list of keycodes that are not allowed when the polyfill is configured to hide-on-input
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badKeys = [
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// The following keys all cause the caret to jump to the end of the input value
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27, // Escape
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33, // Page up
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34, // Page down
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35, // End
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36, // Home
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// Arrow keys allow you to move the caret manually, which should be prevented when the placeholder is visible
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37, // Left
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38, // Up
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39, // Right
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40, // Down
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// The following keys allow you to modify the placeholder text by removing characters, which should be prevented when the placeholder is visible
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8, // Backspace
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46 // Delete
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],
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// Styling variables
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placeholderStyleColor = "#ccc",
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placeholderClassName = "placeholdersjs",
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classNameRegExp = new RegExp("(?:^|\\s)" + placeholderClassName + "(?!\\S)"),
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// These will hold references to all elements that can be affected. NodeList objects are live, so we only need to get those references once
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inputs, textareas,
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// The various data-* attributes used by the polyfill
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ATTR_CURRENT_VAL = "data-placeholder-value",
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ATTR_ACTIVE = "data-placeholder-active",
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ATTR_INPUT_TYPE = "data-placeholder-type",
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ATTR_FORM_HANDLED = "data-placeholder-submit",
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ATTR_EVENTS_BOUND = "data-placeholder-bound",
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ATTR_OPTION_FOCUS = "data-placeholder-focus",
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ATTR_OPTION_LIVE = "data-placeholder-live",
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ATTR_MAXLENGTH = "data-placeholder-maxlength",
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// Various other variables used throughout the rest of the script
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test = document.createElement("input"),
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head = document.getElementsByTagName("head")[0],
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root = document.documentElement,
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Placeholders = global.Placeholders,
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Utils = Placeholders.Utils,
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hideOnInput, liveUpdates, keydownVal, styleElem, styleRules, placeholder, timer, form, elem, len, i;
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// No-op (used in place of public methods when native support is detected)
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function noop() {}
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// Avoid IE9 activeElement of death when an iframe is used.
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// More info:
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// http://bugs.jquery.com/ticket/13393
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// https://github.com/jquery/jquery/commit/85fc5878b3c6af73f42d61eedf73013e7faae408
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function safeActiveElement() {
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try {
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return document.activeElement;
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} catch (err) {}
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}
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// Hide the placeholder value on a single element. Returns true if the placeholder was hidden and false if it was not (because it wasn't visible in the first place)
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function hidePlaceholder(elem, keydownValue) {
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var type,
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maxLength,
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valueChanged = (!!keydownValue && elem.value !== keydownValue),
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isPlaceholderValue = (elem.value === elem.getAttribute(ATTR_CURRENT_VAL));
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if ((valueChanged || isPlaceholderValue) && elem.getAttribute(ATTR_ACTIVE) === "true") {
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elem.removeAttribute(ATTR_ACTIVE);
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elem.value = elem.value.replace(elem.getAttribute(ATTR_CURRENT_VAL), "");
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elem.className = elem.className.replace(classNameRegExp, "");
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// Restore the maxlength value
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maxLength = elem.getAttribute(ATTR_MAXLENGTH);
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if (parseInt(maxLength, 10) >= 0) { // Old FF returns -1 if attribute not set (see GH-56)
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elem.setAttribute("maxLength", maxLength);
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elem.removeAttribute(ATTR_MAXLENGTH);
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}
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// If the polyfill has changed the type of the element we need to change it back
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type = elem.getAttribute(ATTR_INPUT_TYPE);
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if (type) {
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elem.type = type;
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}
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return true;
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}
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return false;
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}
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// Show the placeholder value on a single element. Returns true if the placeholder was shown and false if it was not (because it was already visible)
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function showPlaceholder(elem) {
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var type,
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maxLength,
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val = elem.getAttribute(ATTR_CURRENT_VAL);
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if (elem.value === "" && val) {
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elem.setAttribute(ATTR_ACTIVE, "true");
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elem.value = val;
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elem.className += " " + placeholderClassName;
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// Store and remove the maxlength value
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maxLength = elem.getAttribute(ATTR_MAXLENGTH);
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if (!maxLength) {
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elem.setAttribute(ATTR_MAXLENGTH, elem.maxLength);
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elem.removeAttribute("maxLength");
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}
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// If the type of element needs to change, change it (e.g. password inputs)
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type = elem.getAttribute(ATTR_INPUT_TYPE);
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if (type) {
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elem.type = "text";
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} else if (elem.type === "password") {
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if (Utils.changeType(elem, "text")) {
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elem.setAttribute(ATTR_INPUT_TYPE, "password");
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}
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}
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return true;
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}
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return false;
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}
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function handleElem(node, callback) {
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var handleInputsLength, handleTextareasLength, handleInputs, handleTextareas, elem, len, i;
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// Check if the passed in node is an input/textarea (in which case it can't have any affected descendants)
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if (node && node.getAttribute(ATTR_CURRENT_VAL)) {
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callback(node);
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} else {
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// If an element was passed in, get all affected descendants. Otherwise, get all affected elements in document
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handleInputs = node ? node.getElementsByTagName("input") : inputs;
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handleTextareas = node ? node.getElementsByTagName("textarea") : textareas;
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handleInputsLength = handleInputs ? handleInputs.length : 0;
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handleTextareasLength = handleTextareas ? handleTextareas.length : 0;
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// Run the callback for each element
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for (i = 0, len = handleInputsLength + handleTextareasLength; i < len; i++) {
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elem = i < handleInputsLength ? handleInputs[i] : handleTextareas[i - handleInputsLength];
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callback(elem);
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}
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}
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}
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// Return all affected elements to their normal state (remove placeholder value if present)
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function disablePlaceholders(node) {
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handleElem(node, hidePlaceholder);
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}
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// Show the placeholder value on all appropriate elements
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function enablePlaceholders(node) {
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handleElem(node, showPlaceholder);
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}
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// Returns a function that is used as a focus event handler
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function makeFocusHandler(elem) {
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return function () {
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// Only hide the placeholder value if the (default) hide-on-focus behaviour is enabled
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if (hideOnInput && elem.value === elem.getAttribute(ATTR_CURRENT_VAL) && elem.getAttribute(ATTR_ACTIVE) === "true") {
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// Move the caret to the start of the input (this mimics the behaviour of all browsers that do not hide the placeholder on focus)
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Utils.moveCaret(elem, 0);
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} else {
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// Remove the placeholder
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hidePlaceholder(elem);
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}
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};
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}
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// Returns a function that is used as a blur event handler
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function makeBlurHandler(elem) {
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return function () {
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showPlaceholder(elem);
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};
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}
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// Functions that are used as a event handlers when the hide-on-input behaviour has been activated - very basic implementation of the "input" event
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function makeKeydownHandler(elem) {
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return function (e) {
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keydownVal = elem.value;
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//Prevent the use of the arrow keys (try to keep the cursor before the placeholder)
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if (elem.getAttribute(ATTR_ACTIVE) === "true") {
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if (keydownVal === elem.getAttribute(ATTR_CURRENT_VAL) && Utils.inArray(badKeys, e.keyCode)) {
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if (e.preventDefault) {
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e.preventDefault();
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}
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return false;
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}
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}
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};
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}
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function makeKeyupHandler(elem) {
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return function () {
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hidePlaceholder(elem, keydownVal);
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// If the element is now empty we need to show the placeholder
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if (elem.value === "") {
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elem.blur();
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Utils.moveCaret(elem, 0);
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}
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};
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}
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function makeClickHandler(elem) {
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return function () {
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if (elem === safeActiveElement() && elem.value === elem.getAttribute(ATTR_CURRENT_VAL) && elem.getAttribute(ATTR_ACTIVE) === "true") {
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Utils.moveCaret(elem, 0);
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}
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};
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}
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// Returns a function that is used as a submit event handler on form elements that have children affected by this polyfill
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function makeSubmitHandler(form) {
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return function () {
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// Turn off placeholders on all appropriate descendant elements
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disablePlaceholders(form);
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};
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}
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// Bind event handlers to an element that we need to affect with the polyfill
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function newElement(elem) {
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// If the element is part of a form, make sure the placeholder string is not submitted as a value
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if (elem.form) {
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form = elem.form;
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// If the type of the property is a string then we have a "form" attribute and need to get the real form
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if (typeof form === "string") {
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form = document.getElementById(form);
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}
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// Set a flag on the form so we know it's been handled (forms can contain multiple inputs)
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if (!form.getAttribute(ATTR_FORM_HANDLED)) {
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Utils.addEventListener(form, "submit", makeSubmitHandler(form));
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form.setAttribute(ATTR_FORM_HANDLED, "true");
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}
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}
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// Bind event handlers to the element so we can hide/show the placeholder as appropriate
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Utils.addEventListener(elem, "focus", makeFocusHandler(elem));
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Utils.addEventListener(elem, "blur", makeBlurHandler(elem));
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// If the placeholder should hide on input rather than on focus we need additional event handlers
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if (hideOnInput) {
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Utils.addEventListener(elem, "keydown", makeKeydownHandler(elem));
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Utils.addEventListener(elem, "keyup", makeKeyupHandler(elem));
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Utils.addEventListener(elem, "click", makeClickHandler(elem));
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}
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// Remember that we've bound event handlers to this element
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elem.setAttribute(ATTR_EVENTS_BOUND, "true");
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elem.setAttribute(ATTR_CURRENT_VAL, placeholder);
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// If the element doesn't have a value and is not focussed, set it to the placeholder string
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if (hideOnInput || elem !== safeActiveElement()) {
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showPlaceholder(elem);
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}
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}
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Placeholders.nativeSupport = test.placeholder !== void 0;
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if (!Placeholders.nativeSupport) {
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// Get references to all the input and textarea elements currently in the DOM (live NodeList objects to we only need to do this once)
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inputs = document.getElementsByTagName("input");
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textareas = document.getElementsByTagName("textarea");
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// Get any settings declared as data-* attributes on the root element (currently the only options are whether to hide the placeholder on focus or input and whether to auto-update)
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hideOnInput = root.getAttribute(ATTR_OPTION_FOCUS) === "false";
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liveUpdates = root.getAttribute(ATTR_OPTION_LIVE) !== "false";
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// Create style element for placeholder styles (instead of directly setting style properties on elements - allows for better flexibility alongside user-defined styles)
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styleElem = document.createElement("style");
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styleElem.type = "text/css";
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// Create style rules as text node
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styleRules = document.createTextNode("." + placeholderClassName + " { color:" + placeholderStyleColor + "; }");
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// Append style rules to newly created stylesheet
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if (styleElem.styleSheet) {
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styleElem.styleSheet.cssText = styleRules.nodeValue;
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} else {
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styleElem.appendChild(styleRules);
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}
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// Prepend new style element to the head (before any existing stylesheets, so user-defined rules take precedence)
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head.insertBefore(styleElem, head.firstChild);
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// Set up the placeholders
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for (i = 0, len = inputs.length + textareas.length; i < len; i++) {
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elem = i < inputs.length ? inputs[i] : textareas[i - inputs.length];
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// Get the value of the placeholder attribute, if any. IE10 emulating IE7 fails with getAttribute, hence the use of the attributes node
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placeholder = elem.attributes.placeholder;
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if (placeholder) {
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// IE returns an empty object instead of undefined if the attribute is not present
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placeholder = placeholder.nodeValue;
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// Only apply the polyfill if this element is of a type that supports placeholders, and has a placeholder attribute with a non-empty value
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if (placeholder && Utils.inArray(validTypes, elem.type)) {
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newElement(elem);
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}
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}
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}
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// If enabled, the polyfill will repeatedly check for changed/added elements and apply to those as well
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timer = setInterval(function () {
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for (i = 0, len = inputs.length + textareas.length; i < len; i++) {
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elem = i < inputs.length ? inputs[i] : textareas[i - inputs.length];
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// Only apply the polyfill if this element is of a type that supports placeholders, and has a placeholder attribute with a non-empty value
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placeholder = elem.attributes.placeholder;
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if (placeholder) {
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placeholder = placeholder.nodeValue;
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if (placeholder && Utils.inArray(validTypes, elem.type)) {
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// If the element hasn't had event handlers bound to it then add them
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if (!elem.getAttribute(ATTR_EVENTS_BOUND)) {
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newElement(elem);
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}
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// If the placeholder value has changed or not been initialised yet we need to update the display
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if (placeholder !== elem.getAttribute(ATTR_CURRENT_VAL) || (elem.type === "password" && !elem.getAttribute(ATTR_INPUT_TYPE))) {
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// Attempt to change the type of password inputs (fails in IE < 9)
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if (elem.type === "password" && !elem.getAttribute(ATTR_INPUT_TYPE) && Utils.changeType(elem, "text")) {
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elem.setAttribute(ATTR_INPUT_TYPE, "password");
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}
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// If the placeholder value has changed and the placeholder is currently on display we need to change it
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if (elem.value === elem.getAttribute(ATTR_CURRENT_VAL)) {
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elem.value = placeholder;
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}
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// Keep a reference to the current placeholder value in case it changes via another script
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elem.setAttribute(ATTR_CURRENT_VAL, placeholder);
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}
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}
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} else if (elem.getAttribute(ATTR_ACTIVE)) {
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hidePlaceholder(elem);
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elem.removeAttribute(ATTR_CURRENT_VAL);
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}
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}
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// If live updates are not enabled cancel the timer
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if (!liveUpdates) {
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clearInterval(timer);
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}
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}, 100);
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}
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Utils.addEventListener(global, "beforeunload", function () {
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Placeholders.disable();
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});
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// Expose public methods
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Placeholders.disable = Placeholders.nativeSupport ? noop : disablePlaceholders;
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Placeholders.enable = Placeholders.nativeSupport ? noop : enablePlaceholders;
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}(this));
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