思路:用border实现。
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
<style>
.triggle {
width: 0;
height: 0;
border: 100px solid transparent;
border-left: 100px solid red;
}
</style>
</head>
<body>
<div class="triggle"></div>
</body>
</html>
100是三角形的高,效果如下:三角形底边长200高100
相应的,若是倒三角形,则设置border:100px solid transparent;border-top:100px solid red;即可.
画一个左下角的正三角形,代码如下:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
<style>
.triggle {
width: 0;
height: 0;
border: 100px solid transparent;
border-left: 100px solid red;
border-bottom: 100px solid red;
}
</style>
</head>
<body>
<div class="triggle"></div>
</body>
</html>
效果图: