js中 new Date().getTime()得到的是毫秒数时间戳

function getLocalTime(nS) {     
		var d = new Date(parseInt(nS)* 1000);    //根据时间戳生成的时间对象
		var date = (d.getFullYear()) + "-" + 
					(d.getMonth() + 1) + "-" +
					(d.getDate()) + " " + 
					(d.getHours()) + ":" + 
					(d.getMinutes()) + ":" + 
					(d.getSeconds()); 
		return date;   
}
document.write(getLocalTime(1552889937));

var timestamp = parseInt(new Date().getTime()/1000);    // 当前时间戳
document.write(timestamp);

var now = new Date();
var yy = now.getFullYear();      //年
var mm = now.getMonth() + 1;     //月
var dd = now.getDate();          //日
var hh = now.getHours();         //时
var ii = now.getMinutes();       //分
var ss = now.getSeconds();       //秒
var clock = yy + "-";
if(mm < 10) clock += "0";
clock += mm + "-";
if(dd < 10) clock += "0";
clock += dd + " ";
if(hh < 10) clock += "0";
clock += hh + ":";
if (ii < 10) clock += '0'; 
clock += ii + ":";
if (ss < 10) clock += '0'; 
clock += ss;
document.write(clock);     //获取当前日期

var date = '2015-03-05 17:59:00.0';
date = date.substring(0,19);    
date = date.replace(/-/g,'/'); 
var timestamp = new Date(date).getTime();
document.write(timestamp);

var timestamp = '1425553097';
var d = new Date(timestamp * 1000);    //根据时间戳生成的时间对象
var date = (d.getFullYear()) + "-" + 
           (d.getMonth() + 1) + "-" +
           (d.getDate()) + " " + 
           (d.getHours()) + ":" + 
           (d.getMinutes()) + ":" + 
           (d.getSeconds());
document.write(date);