blinker / firefox.plugin / data / lib / withinViewport.js @ master
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| 1 | a03cd52e | Thies Pfeiffer | /**
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| 2 | * Within Viewport
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| 3 | *
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| 4 | * @description Determines whether an element is completely
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| 5 | * within the browser viewport
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| 6 | * @author Craig Patik, http://patik.com/
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| 7 | * @version 0.0.4
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| 8 | * @date 2014-07-05
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| 9 | */
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| 10 | ;(function() {
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| 11 | /**
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| 12 | * Determines whether an element is within the viewport
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| 13 | * @param {Object} elem DOM Element (required)
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| 14 | * @param {Object} options Optional settings
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| 15 | * @return {Boolean} Whether the element was completely within the viewport
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| 16 | */
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| 17 | var withinViewport = function _withinViewport(elem, options) { |
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| 18 | var result = false, |
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| 19 | metadata = {},
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| 20 | config = {},
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| 21 | settings, useHtmlElem, isWithin, scrollOffset, elemOffset, arr, i, side; |
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| 22 | |||
| 23 | if (typeof jQuery !== 'undefined' && elem instanceof jQuery) { |
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| 24 | elem = elem.get(0);
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| 25 | } |
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| 26 | |||
| 27 | if (typeof elem !== 'object' || elem.nodeType !== 1) { |
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| 28 | throw new Error('First argument must be an element'); |
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| 29 | } |
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| 30 | |||
| 31 | if (elem.getAttribute('data-withinviewport-settings') && window.JSON) { |
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| 32 | metadata = JSON.parse(elem.getAttribute('data-withinviewport-settings'));
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| 33 | } |
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| 34 | |||
| 35 | // Settings argument may be a simple string (`top`, `right`, etc)
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| 36 | if (typeof options === 'string') { |
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| 37 | settings = {sides: options};
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| 38 | } |
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| 39 | else {
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| 40 | settings = options || {};
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| 41 | } |
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| 42 | |||
| 43 | // Build configuration from defaults and given settings
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| 44 | config.container = settings.container || metadata.container || withinViewport.defaults.container || document.body; |
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| 45 | config.sides = settings.sides || metadata.sides || withinViewport.defaults.sides || 'all';
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| 46 | config.top = settings.top || metadata.top || withinViewport.defaults.top || 0;
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| 47 | config.right = settings.right || metadata.right || withinViewport.defaults.right || 0;
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| 48 | config.bottom = settings.bottom || metadata.bottom || withinViewport.defaults.bottom || 0;
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| 49 | config.left = settings.left || metadata.left || withinViewport.defaults.left || 0;
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| 50 | |||
| 51 | // Whether we can use the `<html`> element for `scrollTop`
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| 52 | // Unfortunately at the moment I can't find a way to do this without UA-sniffing
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| 53 | useHtmlElem = !/Chrome/.test(navigator.userAgent);
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| 54 | |||
| 55 | // Element testing methods
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| 56 | isWithin = {
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| 57 | // Element is below the top edge of the viewport
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| 58 | top: function _isWithin_top() { |
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| 59 | return elemOffset[1] >= scrollOffset[1] + config.top; |
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| 60 | }, |
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| 61 | |||
| 62 | // Element is to the left of the right edge of the viewport
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| 63 | right: function _isWithin_right() { |
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| 64 | var container = (config.container === document.body) ? window : config.container;
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| 65 | |||
| 66 | return elemOffset[0] + elem.offsetWidth <= container.innerWidth + scrollOffset[0] - config.right; |
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| 67 | }, |
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| 68 | |||
| 69 | // Element is above the bottom edge of the viewport
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| 70 | bottom: function _isWithin_bottom() { |
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| 71 | var container = (config.container === document.body) ? window : config.container;
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| 72 | |||
| 73 | return elemOffset[1] + elem.offsetHeight <= scrollOffset[1] + container.innerHeight - config.bottom; |
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| 74 | }, |
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| 75 | |||
| 76 | // Element is to the right of the left edge of the viewport
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| 77 | left: function _isWithin_left() { |
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| 78 | return elemOffset[0] >= scrollOffset[0] + config.left; |
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| 79 | }, |
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| 80 | |||
| 81 | all: function _isWithin_all() { |
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| 82 | return (isWithin.top() && isWithin.right() && isWithin.bottom() && isWithin.left());
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| 83 | } |
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| 84 | }; |
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| 85 | |||
| 86 | // Current offset values
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| 87 | scrollOffset = (function _scrollOffset() { |
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| 88 | var x = config.container.scrollLeft,
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| 89 | y = config.container.scrollTop; |
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| 90 | |||
| 91 | if (y === 0) { |
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| 92 | if (config.container.pageYOffset) {
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| 93 | y = config.container.pageYOffset; |
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| 94 | } |
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| 95 | else if (window.pageYOffset) { |
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| 96 | y = window.pageYOffset; |
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| 97 | } |
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| 98 | else {
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| 99 | if (config.container === document.body) {
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| 100 | if (useHtmlElem) {
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| 101 | y = (config.container.parentElement) ? config.container.parentElement.scrollTop : 0;
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| 102 | } |
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| 103 | else {
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| 104 | y = (config.container.parentElement) ? config.container.parentElement.scrollTop : 0;
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| 105 | } |
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| 106 | } |
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| 107 | else {
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| 108 | y = (config.container.parentElement) ? config.container.parentElement.scrollTop : 0;
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| 109 | } |
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| 110 | } |
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| 111 | } |
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| 112 | |||
| 113 | if (x === 0) { |
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| 114 | if (config.container.pageXOffset) {
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| 115 | x = config.container.pageXOffset; |
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| 116 | } |
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| 117 | else if (window.pageXOffset) { |
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| 118 | x = window.pageXOffset; |
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| 119 | } |
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| 120 | else {
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| 121 | if (config.container === document.body) {
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| 122 | x = (config.container.parentElement) ? config.container.parentElement.scrollLeft : 0;
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| 123 | } |
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| 124 | else {
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| 125 | x = (config.container.parentElement) ? config.container.parentElement.scrollLeft : 0;
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| 126 | } |
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| 127 | } |
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| 128 | } |
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| 129 | |||
| 130 | return [x, y];
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| 131 | }()); |
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| 132 | |||
| 133 | elemOffset = (function _elemOffset() { |
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| 134 | var el = elem,
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| 135 | x = 0,
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| 136 | y = 0;
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| 137 | |||
| 138 | if (el.parentNode) {
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| 139 | x = el.offsetLeft; |
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| 140 | y = el.offsetTop; |
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| 141 | |||
| 142 | el = el.parentNode; |
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| 143 | while (el) {
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| 144 | if (el == config.container) {
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| 145 | break;
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| 146 | } |
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| 147 | |||
| 148 | x += el.offsetLeft; |
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| 149 | y += el.offsetTop; |
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| 150 | |||
| 151 | el = el.parentNode; |
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| 152 | } |
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| 153 | } |
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| 154 | |||
| 155 | return [x, y];
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| 156 | })(); |
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| 157 | |||
| 158 | // Test the element against each side of the viewport that was requested
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| 159 | arr = config.sides.split(' ');
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| 160 | i = arr.length; |
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| 161 | while (i--) {
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| 162 | side = arr[i].toLowerCase(); |
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| 163 | if (/top|right|bottom|left|all/.test(side)) { |
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| 164 | if (isWithin[side]()) {
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| 165 | result = true;
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| 166 | } |
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| 167 | else {
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| 168 | result = false;
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| 169 | // Quit as soon as the first failure is found
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| 170 | break;
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| 171 | } |
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| 172 | } |
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| 173 | } |
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| 174 | |||
| 175 | return result;
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| 176 | }; // end of `withinViewport()`
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| 177 | |||
| 178 | // Default settings
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| 179 | withinViewport.prototype.defaults = {
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| 180 | container: document.body,
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| 181 | sides: 'all', |
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| 182 | top: 0, |
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| 183 | right: 0, |
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| 184 | bottom: 0, |
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| 185 | left: 0 |
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| 186 | }; |
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| 187 | |||
| 188 | withinViewport.defaults = withinViewport.prototype.defaults; |
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| 189 | |||
| 190 | // Make function available globally
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| 191 | window.withinViewport = withinViewport; |
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| 192 | |||
| 193 | /**
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| 194 | * Optional enhancements and shortcuts
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| 195 | *
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| 196 | * @description Uncomment or comment these pieces as they apply to your project and coding preferences
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| 197 | */
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| 198 | |||
| 199 | // Shortcut methods for each side of the viewport
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| 200 | // Ex: withinViewport.top(elem) is the same as withinViewport(elem, 'top')
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| 201 | withinViewport.prototype.top = function _withinViewport_top(element) { |
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| 202 | return withinViewport(element, 'top'); |
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| 203 | }; |
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| 204 | |||
| 205 | withinViewport.prototype.right = function _withinViewport_right(element) { |
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| 206 | return withinViewport(element, 'right'); |
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| 207 | }; |
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| 208 | |||
| 209 | withinViewport.prototype.bottom = function _withinViewport_bottom(element) { |
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| 210 | return withinViewport(element, 'bottom'); |
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| 211 | }; |
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| 212 | |||
| 213 | withinViewport.prototype.left = function _withinViewport_left(element) { |
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| 214 | return withinViewport(element, 'left'); |
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| 215 | }; |
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| 216 | }()); |