$("button").click(function () {
$("ul").toggle();
});<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<button> <img src="/images/default_avatar.jpg">Hello!<i class="fa fa-chevron-up"></i> </button>
<ul style="display:none;">
<li><a href="#">Account settings</a></li>
<li><a href="#">Logout</a></li>
</ul>我有一个按钮，它有一个 V 形向上和一个列表，我想要做的是显示列表并在切换时隐藏它，我做到了，我希望 V 形向上也可以在切换时更改为向上和向下，我怎样才能做到这一点？这是我的代码：
我有一个圆圈，它的背景颜色设置为红色，我想在悬停时使用 css 动画更改其背景，我该怎么做？这是我的代码：
.circle{
background-color: red;
border-radius: 50px;
height: 100px;
width: 100px;
}<html>
<body>
<div class="circle"></div>
</body>
</html>我有一个旋转木马,我试图用圆形图像替换指标,每当我这样做时图像出现但指标不会消失,我想移动指标并保持图像作为指标,我想移动指标在左边,我该怎么做？这是我的代码:
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css" integrity="sha384-BVYiiSIFeK1dGmJRAkycuHAHRg32OmUcww7on3RYdg4Va+PmSTsz/K68vbdEjh4u" crossorigin="anonymous">
<div id="carousel-example-generic" class="carousel slide" data-ride="carousel">
<!-- Indicators -->
<ol class="carousel-indicators">
<li data-target="#carousel-example-generic" data-slide-to="0" class="active"><img src=" http://placehold.it/140x100" alt="...">
</li>
<li data-target="#carousel-example-generic" data-slide-to="1"></li>
<li data-target="#carousel-example-generic" data-slide-to="2"></li>
</ol>
<!-- Wrapper for slides -->
<div class="carousel-inner" role="listbox">
<div class="item active">
<img src=" http://placehold.it/350x150" alt="...">
<div class="carousel-caption">
...
</div>
</div>
<div class="item">
<img src=" http://placehold.it/350x150" alt="...">
<div class="carousel-caption">
...
</div>
</div>
...
</div>
<!-- Controls -->
<a class="left carousel-control" href="#carousel-example-generic" role="button" data-slide="prev">
<span class="glyphicon glyphicon-chevron-left" aria-hidden="true"></span>
<span …我有一个按钮，我想在单击时将其背景颜色更改为白色，然后当我再次单击时它返回到原始背景颜色，我该怎么做？这是我的代码：
$(document).ready(function () {
$("button").click(function () {
$(this).css("background-color", "#FFF");
});
});<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<button>Hello</button>我有一个按钮被禁用，我想在里面放一个计数器，我想做的是当计数器达到零时它被启用，我该怎么做？在下面的代码中，计数器没有出现在按钮内，我不想要重置按钮，我只想在按钮达到零时启用按钮，这是我迄今为止尝试过的：
function Countdown()
{
this.start_time = "00:30";
this.target_id = "#timer";
this.name = "timer";
this.reset_btn = "#reset";
}
Countdown.prototype.init = function()
{
this.reset();
setInterval(this.name + '.tick()',1000)
}
Countdown.prototype.reset = function()
{
$(this.reset_btn).hide();
time = this.start_time.split(":");
//this.minutes = parseInt(time[0]);
this.seconds = parseInt(time[1]);
this.update_target();
}
Countdown.prototype.tick = function()
{
if(this.seconds > 0) //|| this.minutes > 0)
{
if(this.seconds == 0)
{
// this.minutes = this.minutes - 1;
this.seconds = 59
} else {
this.seconds = this.seconds - 1;
}
}
this.update_target()
}
Countdown.prototype.update_target …