93 lines
2.9 KiB
JavaScript
93 lines
2.9 KiB
JavaScript
/**
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* @file
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* JavaScript behaviors for webform scroll top.
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*/
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(function ($, Drupal) {
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'use strict';
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Drupal.webform = Drupal.webform || {};
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// Allow scrollTopOffset to be custom defined or based on whether there is a
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// floating toolbar.
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Drupal.webform.scrollTopOffset = Drupal.webform.scrollTopOffset || ($('#toolbar-administration').length ? 140 : 10);
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/**
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* Scroll to top ajax command.
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*
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* @param {Element} element
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* The element to scroll to.
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* @param {string} target
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* Scroll to target. (form or page)
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*/
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Drupal.webformScrollTop = function (element, target) {
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if (!target) {
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return;
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}
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var $element = $(element);
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// Scroll to the top of the view. This will allow users
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// to browse newly loaded content after e.g. clicking a pager
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// link.
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var offset = $element.offset();
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// We can't guarantee that the scrollable object should be
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// the body, as the view could be embedded in something
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// more complex such as a modal popup. Recurse up the DOM
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// and scroll the first element that has a non-zero top.
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var $scrollTarget = $element;
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while ($scrollTarget.scrollTop() === 0 && $($scrollTarget).parent()) {
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$scrollTarget = $scrollTarget.parent();
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}
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if (target === 'page' && $scrollTarget.length && $scrollTarget[0].tagName === 'HTML') {
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// Scroll to top when scroll target is the entire page.
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// @see https://stackoverflow.com/questions/123999/how-to-tell-if-a-dom-element-is-visible-in-the-current-viewport
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var rect = $($scrollTarget)[0].getBoundingClientRect();
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if (!(rect.top >= 0 && rect.left >= 0 && rect.bottom <= $(window).height() && rect.right <= $(window).width())) {
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$scrollTarget.animate({scrollTop: 0}, 500);
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}
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}
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else {
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// Only scroll upward.
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if (offset.top - Drupal.webform.scrollTopOffset < $scrollTarget.scrollTop()) {
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$scrollTarget.animate({scrollTop: (offset.top - Drupal.webform.scrollTopOffset)}, 500);
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}
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}
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};
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/**
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* Scroll element into view.
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*
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* @param {jQuery} $element
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* An element.
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*/
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Drupal.webformScrolledIntoView = function ($element) {
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if (!Drupal.webformIsScrolledIntoView($element)) {
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$('html, body').animate({scrollTop: $element.offset().top - Drupal.webform.scrollTopOffset}, 500);
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}
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};
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/**
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* Determine if element is visible in the viewport.
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*
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* @param {Element} element
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* An element.
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*
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* @return {boolean}
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* TRUE if element is visible in the viewport.
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*
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* @see https://stackoverflow.com/questions/487073/check-if-element-is-visible-after-scrolling
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*/
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Drupal.webformIsScrolledIntoView = function (element) {
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var docViewTop = $(window).scrollTop();
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var docViewBottom = docViewTop + $(window).height();
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var elemTop = $(element).offset().top;
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var elemBottom = elemTop + $(element).height();
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return ((elemBottom <= docViewBottom) && (elemTop >= docViewTop));
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};
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})(jQuery, Drupal);
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