javascript中日期格式与时间戳之间的转化

function timeTodate(date)
{
    var new_str = date.replace(/:/g,'-');
    new_str = new_str.replace(/ /g,'-');
    var arr = new_str.split("-");
    var datum = new Date(Date.UTC(arr[0],arr[1]-1,arr[2],arr[3]-8,arr[4],arr[5]));
    return strtotime = datum.getTime()/1000;
}

var str_time = '2013-04-19 23:40:48';
var rst_strto_time = timeTodate(str_time);
document.write("时间戳: "+rst_strto_time);

function dateTotime(date_time)
{
    var timestr = new Date(parseInt(date_time) * 1000);
    var datetime = timestr.toLocaleString().replace(/年|月/g, "-").replace(/日/g, " ");
    return datetime;
}

var strtotime = 1408502536;
var rst_date_time = dateTotime(strtotime );
document.write("日期: "+rst_date_time);