<!DOCTYPE html>
<html>
<head>
???<meta charset="utf-8">
???<meta name="renderer" content="webkit">
???<meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">
???<meta name="viewport" content="width=device-width, initial-scale=1.0, minimum-scale=1.0, maximum-scale=1.0, user-scalable=0">
???<title>时间</title>
</head>
<body>
???<script>
???????function getBeforeDate(n) {
???????????var n = n;
???????????var d = new Date();
???????????var year = d.getFullYear();
???????????var mon = d.getMonth() + 1;
???????????var day = d.getDate();
???????????if (day <= n) {
???????????????if (mon > 1) {
???????????????????mon = mon - 1;
???????????????}
???????????????else {
???????????????????year = year - 1;
???????????????????mon = 12;
???????????????}
???????????}
???????????d.setDate(d.getDate() - n);
???????????year = d.getFullYear();
???????????mon = d.getMonth() + 1;
???????????day = d.getDate();
???????????s = year + "-" + (mon < 10 ? (‘0‘ + mon) : mon) + "-" + (day < 10 ? (‘0‘ + day) : day);
???????????return s;
???????}
???????console.log(getBeforeDate(1));//昨天的日期
console.log(getBeforeDate(2));
console.log(getBeforeDate(3));
console.log(getBeforeDate(4));
console.log(getBeforeDate(5));
console.log(getBeforeDate(6));
???????console.log(getBeforeDate(7));//前七天的日期
???</script>
</body>
</html>
转：JS获取前七天的日期
原文地址：https://www.cnblogs.com/Ly426/p/9768662.html