实现有边缘的三角形小知识，大挑战！本文正在参与“程序员必备小知识”创作活动。 ui图：实现效果：原理：先画一个三角形

ui图：

实现效果：

原理：先画一个三角形，再画白色三角形的，调整几像素位置，覆盖掉一边

附上代码：

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .father-wrap{
            width: 300px;
            height: 300px;
            border: 1px solid red;
            display: flex;
            justify-content: center;
            align-items: center;
        }
        .triangle {
            position: relative;
            width: 100px;
            height: 50px;
            border: 2px solid #4ed621;
            border-radius: 5px;
        }

        .triangle:before {
            position: absolute;
            content: "";
            top: -10px;
            left: 25px;
            border-left: 10px solid transparent;
            border-right: 10px solid transparent;
            border-bottom: 10px solid #4ed621;
        }

        /* 白色覆盖*/
        .triangle:after {
            position: absolute;
            content: "";
            /*减少两像素*/
            top: -8px;
            left: 25px;
            border-left: 10px solid transparent;
            border-right: 10px solid transparent;
            border-bottom: 10px solid #fff;
        }
    </style>
</head>

<body>

    <div class="father-wrap">
        <div class="triangle"></div>
    </div>



</body>

</html>