基于JS快速实现导航下拉菜单动画效果附源码下载

 
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 function morphDropdown( element ) { this.element = element; this.mainNavigation = this.element.find('.main-nav'); this.mainNavigationItems = this.mainNavigation.find('.has-dropdown'); this.dropdownList = this.element.find('.dropdown-list'); //... this.bindEvents(); } bindEvents()方法用于在.has-dropdown和.dropdown元素上检测鼠标进入和鼠标离开事件。 morphDropdown.prototype.bindEvents = function() { var self = this; this.mainNavigationItems.mouseenter(function(event){ //hover over one of the nav items -> show dropdown self.showDropdown($(this)); }).mouseleave(function(){ //if not hovering over a nav item or a dropdown -> hide dropdown if( self.mainNavigation.find('.has-dropdown:hover').length == 0 && self.element.find('.dropdown-list:hover').length == 0 ) self.hideDropdown(); }); //... }; showDropdown方法用于处理宽度、高度和.dropdown-list元素的translateX值，以及放大和缩小.bg-layer元素。 morphDropdown.prototype.showDropdown = function(item) { var selectedDropdown = this.dropdownList.find('#'+item.data('content')), selectedDropdownHeight = selectedDropdown.innerHeight(), selectedDropdownWidth = selectedDropdown.children('.content').innerWidth(), selectedDropdownLeft = item.offset().left + item.innerWidth()/2 - selectedDropdownWidth/2; //update dropdown and dropdown background position and size this.updateDropdown(selectedDropdown, parseInt(selectedDropdownHeight), selectedDropdownWidth, parseInt(selectedDropdownLeft)); //add the .active class to the selected .dropdown and .is-dropdown-visible to the .cd-morph-dropdown //... }; morphDropdown.prototype.updateDropdown = function(dropdownItem, height, width, left) { this.dropdownList.css({ '-moz-transform': 'translateX(' + left + 'px)', '-webkit-transform': 'translateX(' + left + 'px)', '-ms-transform': 'translateX(' + left + 'px)', '-o-transform': 'translateX(' + left + 'px)', 'transform': 'translateX(' + left + 'px)', 'width': width+'px', 'height': height+'px' }); this.dropdownBg.css({ '-moz-transform': 'scaleX(' + width + ') scaleY(' + height + ')', '-webkit-transform': 'scaleX(' + width + ') scaleY(' + height + ')', '-ms-transform': 'scaleX(' + width + ') scaleY(' + height + ')', '-o-transform': 'scaleX(' + width + ') scaleY(' + height + ')', 'transform': 'scaleX(' + width + ') scaleY(' + height + ')' }); };