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console 命令行工具 X clear

                    
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console
<!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>
        .canvas {
            border: 1px solid red;
        }
    </style>
  </head>
  <body>
    <canvas class="canvas" id="canvas" width="500" height="500"></canvas>

    <script>
      window.onload = function () {
        var canvas = document.getElementsByTagName("canvas")[0];
        var context = canvas.getContext("2d");
        context.beginPath();
        context.fillStyle = "#ccc";
        context.rect(50, 50, 50, 50);
        context.fill();
        context.closePath();

        context.beginPath();
        context.fillStyle = "skyblue";
        context.translate(75, 75);
        context.rotate((45 * Math.PI) / 180);
        context.translate(-75, -75);
        context.rect(50, 50, 50, 50);
        context.fill();
        context.closePath();
      };
    </script>
  </body>
</html>