<canvas id="myCanvas" width="500" height="300"></canvas>
const canvas = document.getElementById('myCanvas');
const ctx = canvas.getContext('2d');

// Устанавливаем цвет заливки
ctx.fillStyle = 'red';

// Рисуем прямоугольник
ctx.fillRect(50, 50, 100, 100);

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External JavaScript

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