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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