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October 31, 2020 03:07
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Infinite loop in JavaScript event handler
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| <html> | |
| <canvas id="canvas" width="300" height="300"></canvas> | |
| <script> | |
| let canvas = document.getElementById('canvas'); | |
| let ctx = canvas.getContext('2d'); | |
| ctx.strokeRect(0, 0, 300, 300); | |
| canvas.addEventListener('click', ev => handle_click(ev)); | |
| function handle_click(ev) { | |
| console.log("click!"); | |
| ctx.strokeRect(ev.offsetX, ev.offsetY, 10, 10); // ← (A) | |
| // Enabling these lines, no rect (A) is shown. | |
| // I expect only the first one rect is drawn? | |
| // | |
| // while (true) { | |
| // console.log("!"); | |
| // } | |
| } | |
| </script> | |
| </html> |
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