JavaScript实现获取当前时间向前推三个月的示例

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<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Test</title>
<script type="text/javascript" language="javascript" >
function get3MonthBefor(){
    var resultDate,year,month,date,hms;
    var currDate = new Date();
    year = currDate.getFullYear();
    month = currDate.getMonth()+1;
    date = currDate.getDate();
    hms = currDate.getHours() + ':' + currDate.getMinutes() + ':' + (currDate.getSeconds() < 10 ? '0'+currDate.getSeconds() : currDate.getSeconds());
    switch(month)
    {
      case 1:
      case 2:
      case 3:
        month += 9;
        year--;
        break;
      default:
        month -= 3;
        break;
    }
    month = (month < 10) ? ('0' + month) : month;
    resultDate = year + '-'+month+'-'+date+' ' + hms;
  return resultDate;
}
document.write(get3MonthBefor());
</script>
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<body>
</body>
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