jQuery下拉菜单导航 下拉自动滑动切换

只有恨少量的JS代码var maxHeight = 400;$(function(){ $(".dropdown > li").hover(function() { var $container = $(this), $list = $container.find("ul"), $anchor = $container.find("a"), height = $list.height() * 1.1, // make sure there is enough room at the bottom multiplier = height / maxHeight; // needs to move faster if list is taller // need to save height here so it can revert on mouseout $container.data("origHeight", $container.height()); // so it can retain it's rollover color all the while the dropdown is open $anchor.addClass("hover"); // make sure dropdown appears directly below parent list item $list .show() .css({ paddingTop: $container.data("origHeight") }); // don't do any animation if list shorter than max if (multiplier > 1) { $container .css({ height: maxHeight, overflow: "hidden" }) .mousemove(function(e) { var offset = $container.offset(); var relativeY = ((e.pageY - offset.top) * multiplier) - ($container.data("origHeight") * multiplier); if (relativeY > $container.data("origHeight")) { $list.css("top", -relativeY + $container.data("origHeight")); }; }); } }, function() { var $el = $(this); // put things back to normal $el .height($(this).data("origHeight")) .find("ul") .css({ top: 0 }) .hide() .end() .find("a") .removeClass("hover"); }); });

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