看看对不对。我再想想
<script>
var dt = new Date()
var y= dt.getYear()
var start = "1/1/"+ y
start = new Date(start)
var days = Math.round((dt.valueOf()- start.valueOf())/(24*60*60*1000))
alert(Math.round(days/7)+1)
</script>
<script>
var dt = new Date()
var y= dt.getYear()
var start = "1/1/"+ y
start = new Date(start)
var days = Math.round((dt.valueOf()- start.valueOf())/(24*60*60*1000))
alert(Math.round(days/7)+1)
</script>
var dt = new Date()
var y= dt.getYear()
var start = "1/1/"+ y
start = new Date(start)
var days = Math.round((dt.valueOf()- start.valueOf())/(24*60*60*1000))
days=days+start.getDay()
alert(Math.floor(days/7)+1)
</script>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<meta name="GENERATOR" content="Microsoft FrontPage 4.0">
<meta name="ProgId" content="FrontPage.Editor.Document">
<title>当前日期在本年中的第几周</title>
</head>
<body>
<script>
//下面的函数摘自以前的帖子,用于计算两个日期之间的天数
function Dayminus(asStartvalue,asEndvalue){
loinStart = asStartvalue.split("-");
loinEnd = asEndvalue.split("-");
var loStart = new Date(loinStart[0],loinStart[1]-1,loinStart[2],0,0,0,0);
var loEnd = new Date(loinEnd[0],loinEnd[1]-1,loinEnd[2],0,0,0,0);
var days=(loEnd.getTime()-loStart.getTime())/(1000*24*3600);
if(days<0) days=-days;
return days;
}var dtoday,yearbeginstr,yearMonday,yearnow,yearbegindtoday=new Date();
yearbeginstr=new Date(dtoday.getYear(),0,1,0,0,0,0)
//本年第一天是星期几
yearMonday=yearbeginstr.getDay()//表示本年首日的日期
yearbegin=dtoday.getYear() + "-1-1"//表示当前的日期
yearnow=dtoday.getYear() + "-" + (parseInt(dtoday.getMonth()) + 1) + "-" + dtoday.getDate()//当前日期在本年中的第几天
daysbetween=Dayminus(yearbegin,yearnow) + 1weeks=parseInt((daysbetween + yearMonday) / 7 ) + 1alert("当前日期在本年中的第" + weeks + "周")
</script>
</body>
</html>
var dt = new Date()
var y= dt.getYear()
var start = "1/1/"+ y
start = new Date(start)
starts = start.valueOf()
startweek = start.getDay()
dtweek = dt.getDay()
var days = Math.round((dt.valueOf()- start.valueOf())/(24*60*60*1000))-(7-startweek) - dt.getDay()-1
days = Math.floor(days/7)
alert(days+2)
</script>
周日做为下周的开始计算