简单的jquery下拉列表 - clearTimeout,setTimeout问题 [英] simple jquery dropdown - clearTimeout, setTimeout issues
问题描述
HTML:
<ul class="topnav">
<li><a href="#"><span>One</span></a></li>
<li><a href="#"><span>Two</span></a></li>
<li>
<li><a href="#"><span>Three</span></a></li>
<ul class="subnav">
<li><a href="#">A</a></li>
<li><a href="#">B</a></li>
<li><a href="#">C</a></li>
</ul>
</li>
</ul>
jquery:
var timeout = null;
$(document).ready(function() {
$("ul.topnav li").mouseover(function() {
if (timeout) clearTimeout(timeout);
$(this).find("ul.subnav").slideDown('fast').show();
}).mouseout(function() {
timeout = setTimeout(closemenu, 500);
});
// sub menu mouseovers keep dropdown open
$("ul.subnav li").mouseover(function() {
if (timeout) clearTimeout(timeout);
}
).mouseout(function() {
timeout = setTimeout(closemenu, 500);
// alert(timeout);
});
// any click closes
$(document).click(closemenu);
});
// Closes all open menus
function closemenu() {
$('ul.subnav:visible').hide();
if (timeout) clearTimeout(timeout);
}
我有超时问题。在使用中,如果我将鼠标悬停在三上,则下拉列表将永远保留下来。如果我鼠标悬停A,下拉菜单将永远保持不动,但如果我将鼠标悬停在B或任何更低的位置,菜单将关闭在我身上。如果你取消注释// alert(timeout);它到达B,(和A),但超时将有一个值。为什么是这样?我认为clearTimeout会使超时变量无效
I'm having issues with timeout. In use, if i mouseover "Three", the dropdown stays out forever. if i mouseover "A", dropdown will stay out forever, but if I mouseover "B" or anything lower, the menu will close on me. if you uncomment "// alert(timeout);" it gets there for B, (and A) but timeout will have a value. why is this? i thought clearTimeout would null the timeout variable?
推荐答案
You can simplify your code overall by using .hover()
and .data()
like this:
$(function() {
$("ul.topnav li").hover(function() {
var timeout = $(this).data("timeout");
if(timeout) clearTimeout(timeout);
$(this).find("ul.subnav").slideDown('fast');
}, function() {
$(this).data("timeout", setTimeout($.proxy(function() {
$(this).find("ul.subnav").slideUp();
}, this), 500));
});
$(document).click(function() {
$('ul.subnav:visible').hide();
});
});
Inste共享一个全局超时
变量,这将设置超级每个顶级< li>
,每个都有一个独立的定时器,当您将鼠标悬停在该元素上时,只有其定时器被清除。另外 .hover()
使用 mouseenter
和 mouseleave
,而不是 mouseover
和 mouseout
,区别在于您进入小孩或儿童之间, mouseenter
doesn' t再次发生火灾,而 mouseleave
不会在我们关心的父级< li>
上触发。
Instead of sharing a global timeout
variable, this sets a timeout per top level <li>
, each one has an independent timer, and when you hover back over that element, only its timer is cleared. Also .hover()
uses mouseenter
and mouseleave
, rather than mouseover
and mouseout
, the difference is when you go into a child or between children, mouseenter
doesn't fire again, and mouseleave
doesn't fire on the parent <li>
we care about.
您可以使用上面的演示链接进行测试,我也将子项目添加到第一个菜单,以演示它们是独立的。如果您对 $。代理
有疑问在那里,它只是在这个超时内的这个
中,匿名函数指的是我想要的(当前的这个
)...超时后需要关闭的元素。
You can test this with the demo link above, I added sub-items to the first menu as well, to demonstrate they're independent. If you happen to have question about the $.proxy
in there, it's just making this
inside that timeout anonymous function refer to what I want it to (the current this
)...the element that needs closing after the timeout.
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