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<html><body><h1>HTML5 Canvas</h1><h2>The getImageData() Method</h2><canvas id="myCanvas" width="300" height="150" style="border:1px solid grey"></canvas><script>const c = document.getElementById("myCanvas");const ctx = c.getContext("2d");ctx.fillStyle = "red";ctx.fillRect(10, 10, 50, 50);var imgData = ctx.getImageData(30, 30, 50, 50);red = imgData.data[0];green = imgData.data[1];blue = imgData.data[2];alpha = imgData.data[3];alert(red + " " + green + " " + blue + " " + alpha);</script></body></html>