1.创建日期对象方法：
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<title>Document</title>
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<script>
// 直接new Date()，返回的是当前日期
let date1 = new Date()
console.log(date1);
// 也可以根据指定的日期，创建一个日期对象
let date2 = new Date('1998-8-8')
console.log(date2);
</script>
</body>
</html>2.也可以根据一个时间戳，创建一个日期对象。时间戳就是：从1970-1-1到指定日期之间的毫秒数：
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<body>
<script>
let date = new Date(123456789)
console.log(date);
</script>
</body>
</html>3.getFullYear() 从 Date 对象返回年份：
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<script>
let date = new Date()
console.log(date.getFullYear());
</script>
</body>
</html>4. getMonth() 从 Date 对象返回月份 (0 ~ 11) 注意：0表示1月份，11表示12月份：
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</head>
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<script>
let date = new Date()
console.log(date.getMonth()+1);
</script>
</body>
</html>5.getDate() 从 Date 对象返回一个月中的某一天 (1 ~ 31) 返回的是几号：
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<title>Document</title>
</head>
<body>
<script>
let date = new Date()
console.log(date.getDate());
</script>
</body>
</html>6.getDay() 从 Date 对象返回一周中的某一天 (0 ~ 6) 返回的是周几
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</head>
<body>
<script>
let date = new Date()
console.log(date.getDay());
</script>
</body>
</html>7.getHours() 返回小时（0-23）：
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<title>Document</title>
</head>
<body>
<script>
let date = new Date()
console.log(date.getHours());
</script>
</body>
</html>8. getMinutes() 返回分钟（0-59）：
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<title>Document</title>
</head>
<body>
<script>
let date = new Date()
console.log(date.getMinutes());
</script>
</body>
</html>9.getSeconds() 返回秒数（0-59）
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<title>Document</title>
</head>
<body>
<script>
let date = new Date()
console.log(date.getSeconds());
</script>
</body>
</html>10.getMilliseconds() 返回毫秒（0-999）
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<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
</head>
<body>
<script>
let date = new Date()
console.log(date.getMilliseconds());
</script>
</body>
</html>11.返回一个当前的时间：代码
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<title>Document</title>
</head>
<body>
<script>
let date = new Date()
console.log(date.getHours()+":"+date.getMinutes()+":"+date.getSeconds()+" "+date.getMilliseconds());
</script>
</body>
</html>