js日期相关

格式化输出日期：
<script type="text/javascript">
Date.prototype.format = function(format)
{
var o = {
"M+" : this.getMonth()+1, //month
"d+" : this.getDate(), //day
"h+" : this.getHours(), //hour
"m+" : this.getMinutes(), //minute
"s+" : this.getSeconds(), //second
"q+" : Math.floor((this.getMonth()+3)/3), //quarter
"S" : this.getMilliseconds() //millisecond
}
if (/(y+)/.test(format))
format=format.replace(RegExp.$1,(this.getFullYear()+"").substr(4 - RegExp.$1.length));
for (var k in o)
if (new RegExp("("+ k +")").test(format))
format = format.replace(RegExp.$1,RegExp.$1.length==1 ? o[k] :("00"+ o[k]).substr((""+ o[k]).length));
return format;
}

//var dateObj = new Date();
//document.write (dateObj.format('yy-MM-dd'));
</script>
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日期的加减：
<script language='javascript'>
var dateObj = new Date();
var onedaymilliseconds = 24*60*60*1000;
var d = dateObj.getTime() + onedaymilliseconds*2; //增加两天
var newdateobj = new Date(d);
document.write(newdateobj);
</script>
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