| <body style="margin:0"> | |
| <canvas id="a"></canvas> | |
| <script> | |
| const imageData = new ImageData(300, 150); | |
| imageData.data.forEach((item, index) => { | |
| imageData.data[index] = 128; | |
| }); | |
| const ctxA = a.getContext('2d'); | |
| ctxA.putImageData(imageData, 0, 0); | |
| </script> | |
| </body> |