javascript日期转换 时间戳转日期格式

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 testDate = new Date( 1320336000000 );//这里必须是整数，毫秒
var testStr = testDate.format("yyyy年MM月dd日hh小时mm分ss秒");
var testStr2 = testDate.format("yyyyMMdd hh:mm:ss");
alert(testStr + " " + testStr2);