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<html lang="en"><head><meta charset="UTF-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><title>补零案例</title>
</head><body><script>// 1.用户输入let num = +prompt('请输入数字')// 2.判断输出 小于10则补零num = num < 10 ? '0' + num : numalert(num)</script>
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