<span style="color: #006600; font-style: italic; "><br></span>
jQuery 可以通过调用
animate
方法添加动画效果, 而且还提供了一套别名, 使用起来很是方便. 其中slideDown
和slideUp
两方法的作用是纵向展开和卷起一个页面元素, 被使用的几率很高, 却一直存在一个小问题.如果目标元素是被外部事件驱动, 当鼠标快速地连续触发外部元素事件, 动画会滞后的反复执行, 相当不美观 演示页面中有一个按钮, 请用鼠标迅速地来回划过...
如果用 jQuery 来实现这样的效果, 该如何处理呢?
<span style="color: #006600; font-style: italic; "><br></span>
其实很简单, 只需在触发元素上的事件设置为延迟处理, 即可避免滞后反复执行的问题. 例如: 当鼠标滑过按钮后 0.2 秒, 菜单才会展开, 如果鼠标离开按钮, 展开的处理将被终止. 也就是说, 想要展开菜单鼠标必须有 0.2 秒的事件停留在按钮上, 那么迅速地划过按钮是无法执行展开事件的. 卷起也是如此.
// 线程 IDs var mouseover_tid = [];
var mouseout_tid = [];
jQuery(document).ready(function(){
jQuery('#menus > li').each(function(index){
jQuery(this).hover(
// 鼠标进入
function(){
var _self = this;
// 停止卷起事件
clearTimeout(mouseout_tid[index]);
// 当鼠标进入超过 0.2 秒, 展开菜单, 并记录到线程 ID 中
mouseover_tid[index] = setTimeout(function() {
jQuery(_self).find('ul:eq(0)').slideDown(200);
}, 400); },
// 鼠标离开 function(){
var _self = this;
// 停止展开事件
clearTimeout(mouseover_tid[index]);
// 当鼠标离开超过 0.2 秒, 卷起菜单, 并记录到线程 ID 中
mouseout_tid[index] = setTimeout(function() {
jQuery(_self).find('ul:eq(0)').slideUp(200);
}, 400);
}
);
});
});
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