formiss3
/
3.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        * {
            margin: 0;
            padding: 0;
        }

        .box{
            margin: 0 auto;
            text-align: center;
        }

        body {
            background-color: aqua;
        }

        .canva {
            border: 1px solid black;
            background-color: azure;
        }
    </style>
    <script>
        window.onload = function(){
            let canva = document.querySelector('.canva')
            let context = canva.getContext('2d');
            context.beginPath();
            context.moveTo(0,0);
            context.lineTo(300,500);
            context.lineTo(400,300);
            context.closePath();
            context.strokeStyle='blue';
            context.lineWidth=10;
            context.stroke();

        }
    </script>
</head>
<body>
    <div class="box">
        <canvas class="canva" width="600" height="600"></canvas>
    </div>
</body>
</html>