极客教程CSS 箭头
什么是CSS箭头
箭头用于用户界面，引导用户并帮助他们理解信息的流动。它们提供视觉线索以导航不同的操作。
箭头是改善用户体验的一种有效方式。它们被用于工具提示、下拉菜单、导航元素等等。这使得引导用户完成一个过程变得更容易。
可以使用以下CSS属性创建箭头：
- transform : 该属性可以通过使用 rotate() 函数旋转元素，来创建箭头图标。rotate()函数接受一个 angle 作为参数，指定旋转的方向和角度。
-
border : 该属性允许我们通过操作元素边框的宽度和高度来创建三角形。
使用transform属性创建CSS箭头
transform 属性可以通过使用 rotate() 函数旋转元素，来创建箭头图标。rotate()函数接受一个 angle 作为参数，指定旋转的方向和角度。
示例
让我们看一个使用transform属性创建箭头的示例。
<html>
<head>
<style>
.arrow-container {
display: flex;
align-items: center;
}
.arrow {
display: inline-block;
margin-right: 30px;
width: 15px;
height: 15px;
border-top: 2px solid #000;
border-right: 2px solid #000;
}
.right-arrow {
transform: rotate(45deg);
}
.left-arrow {
transform: rotate(-135deg);
}
.up-arrow {
transform: rotate(-45deg);
}
.down-arrow {
transform: rotate(135deg);
}
.top-narrow-arrow {
transform: rotate(-45deg) skew(-15deg, -15deg);
}
.top-wide-arrow {
transform: rotate(-45deg) skew(7deg, 7deg);
}
.top-left-arrow {
transform: rotate(-90deg) skew(-10deg, -10deg);
}
.top-right-arrow {
transform: rotate(0) skew(-10deg, -10deg);
}
.bottom-left-arrow {
transform: rotate(180deg) skew(-10deg, -10deg);
}
.bottom-right-arrow {
transform: rotate(90deg) skew(-10deg, -10deg);
}
</style>
</head>
<body>
<p class="arrow-container"><span class="arrow right-arrow"></span> - This arrow points to the right.</p>
<p class="arrow-container"><span class="arrow left-arrow"></span> - This arrow points to the left.</p>
<p class="arrow-container"><span class="arrow up-arrow"></span> - This arrow points upwards.</p>
<p class="arrow-container"><span class="arrow down-arrow"></span> - This arrow points downwards.</p>
<p class="arrow-container"><span class="arrow top-narrow-arrow"></span> - This arrow points top and is narrow.</p>
<p class="arrow-container"><span class="arrow top-wide-arrow"></span> - This arrow points top and is wide.</p>
<p class="arrow-container"><span class="arrow top-left-arrow"></span> - This arrow points top left.</p>
<p class="arrow-container"><span class="arrow top-right-arrow"></span> - This arrow points top right.</p>
<p class="arrow-container"><span class="arrow bottom-left-arrow"></span> - This arrow points bottom left.</p>
<p class="arrow-container"><span class="arrow bottom-right-arrow"></span> - This arrow points bottom right.</p>
</body>
</html>
使用边框创建 CSS 箭头
通过调整元素边框的宽度和高度，利用 边框 属性我们可以创建一个三角形，从而形成一个箭头。
示例
以下示例演示了如何使用 边框 属性来创建箭头：
<html>
<head>
<style>
.arrow-container {
display: flex;
align-items: center;
}
.left-arrow,
.right-arrow,
.up-arrow,
.down-arrow {
width: 0;
height: 0;
margin: 5px;
}
.left-arrow,
.right-arrow {
border-top: 18px solid transparent;
border-bottom: 18px solid transparent;
}
.up-arrow,
.down-arrow {
border-left: 15px solid transparent;
border-right: 15px solid transparent;
}
.right-arrow {
border-left: 25px solid #F10C0C;
}
.left-arrow {
border-right: 25px solid #F10C0C;
}
.up-arrow {
border-bottom: 25px solid #F10C0C;
}
.down-arrow {
border-top: 25px solid #F10C0C;
}
</style>
</head>
<body>
<p class="arrow-container"><span class="right-arrow"></span> - This arrow points to the right.</p>
<p class="arrow-container"><span class="left-arrow"></span> - This arrow points to the left.</p>
<p class="arrow-container"><span class="up-arrow"></span> - This arrow points to the upwards.</p>
<p class="arrow-container"><span class="down-arrow"></span> - This arrow points to the downwards.</p>
</body>
</html>
CSS箭头样式
我们可以使用CSS的 transformations 和 border 属性使箭头看起来更加时尚，如下面的示例所示。
transform-origin: center 属性确保每个箭头的旋转发生在其中心点周围。
示例
下面是一个示例 –
<html>
<head>
<style>
.arrow-container {
display: flex;
align-items: center;
}
.left-arrow,
.right-arrow,
.up-arrow,
.down-arrow {
display: inline-block;
margin: 30px;
width: 15px;
height: 15px;
border-top: 2px solid #F10C0C;
border-left: 2px solid #F10C0C;
transform-origin: center;
}
.right-arrow {
transform: rotate(135deg);
}
.left-arrow {
transform: rotate(-45deg);
}
.up-arrow {
transform: rotate(45deg);
}
.down-arrow {
transform: rotate(-135deg);
}
.right-arrow::after,
.left-arrow::after,
.up-arrow::after,
.down-arrow::after {
content: "";
display: block;
width: 2px;
height: 45px;
background-color: #F10C0C;
transform: rotate(-45deg) translate(15px, 4px);
}
</style>
</head>
<body>
<p class="arrow-container">Right Arrow - <span class="right-arrow"></span></p>
<p class="arrow-container">Left Arrow - <span class="left-arrow"></span></p>
<p class="arrow-container">Up Arrow - <span class="up-arrow"></span></p>
<p class="arrow-container">Down Arrow - <span class="down-arrow"></span></p>
</body>
</html>
下拉箭头
您可以创建一个带有向下箭头图标的下拉按钮。当您悬停在按钮上时，下拉菜单会出现。
示例
这是一个示例 –
<html>
<head>
<style>
.dropdown {
position: relative;
display: inline-block;
width:98px;
}
.dropdown-btn {
background-color: #F10C0C;
color: #ffffff;
padding: 10px;
border: none;
cursor: pointer;
display: flex;
align-items: center;
}
.dropdown-content {
width:98px;
display: none;
position: absolute;
background-color: #F10C0C;
box-shadow: 0px 8px 16px 0px rgba(0, 0, 0, 0.2);
z-index: 1;
}
.dropdown-btn::after {
content: "";
width: 0;
height: 0;
border-left: 6px solid transparent;
border-right: 6px solid transparent;
border-top: 6px solid white;
margin-left: 5px;
}
.dropdown:hover .dropdown-content {
display: block;
}
.dropdown-item {
padding: 10px;
text-decoration: none;
color: #ffffff;
display: block;
}
</style>
</head>
<body>
<div class="dropdown">
<button class="dropdown-btn">Dropdown</button>
<div class="dropdown-content">
<a href="#" class="dropdown-item">Item 1</a>
<a href="#" class="dropdown-item">Item 2</a>
<a href="#" class="dropdown-item">Item 3</a>
</div>
</div>
</body>
</html>
提示箭头
我们可以使用CSS的 borders 和 transform 属性来创建带有朝上三角箭头的提示。当鼠标悬停在文本上时，提示将显示，当鼠标光标移开时，提示将消失。
示例
下面是一个示例：
<html>
<head>
<style>
.tooltip {
position: relative;
display: inline-block;
cursor: pointer;
}
.tooltipcontent {
display: none;
position: absolute;
background-color: #F10C0C;
color: #fff;
padding: 8px;
border-radius: 4px;
z-index: 1;
font-size: 14px;
white-space: nowrap;
}
.tooltip:hover .tooltipcontent {
display: block;
}
.tooltipcontent::before {
content: "";
position: absolute;
border-width: 6px;
border-style: solid;
border-color: transparent transparent #F10C0C transparent;
top: -12px;
left: 50%;
transform: translateX(-50%);
}
</style>
</head>
<body>
<p>Bring the cursor over Tutorials Point to see the result </p>
<h3 class="tooltip">Tutorials Point
<span class="tooltipcontent">CSS - Arrow</span>
</h3>
</body>
</html>
动态CSS箭头
通过使用CSS动画，我们可以创建移动和脉动的箭头，为网页添加动态效果。以下示例演示了一个向上和向下移动的动画箭头。为了创建一个动态箭头，我们在CSS中使用了 @keyframes 规则来定义一组将应用于箭头的动画。
<html>
<head>
<style>
.arrow-container {
display: flex;
align-items: center;
}
.left-arrow
{
width: 0;
height: 0;
margin: 5px;
}
.left-arrow
{
border-top: 18px solid transparent;
border-bottom: 18px solid transparent;
}
.left-arrow {
border-right: 25px solid #F10C0C;
}
.arrow-move {
position: relative;
animation: move 2s ease-in-out infinite;
}
@keyframes move {
0% {
transform: translateY(0);
}
50% {
transform: translateY(-10px);
}
100% {
transform: translateY(0);
}
}
</style>
</head>
<body>
<p class="arrow-container"><span class="left-arrow arrow-move"></span> - This arrow points to the left.</p>
</body>
</html>