如果只是将当前时间转成时间戳，可以直接使用new Date().getTime()/1000；但如果是将某个具体时间或日期转成Unix时间戳，ie不支持像new Date(“2013-1-1”)  这样带参数的方法，将返回NaN。

对此，我写了以下函数，支持ie6+，谷歌，火狐等浏览器：

复制代码 代码如下:
function getTime(day){
 re = /(\d{4})("2013-02-03 10:10:10"));
alert(getTime("2013-02-03"));
alert(getTime("2013-02"));
alert(getTime("2013"));

下面这个将时间戳转换成日期格式的函数，支持自定义的日期格式，效果类似PHP的date函数，同样支持ie6+，谷歌，火狐等浏览器。这个函数是网友实现的，以后有时间我也写一个出来 ^_^

复制代码 代码如下:
function date(format, timestamp){
    var a, jsdate=((timestamp) "").length < c){
            return new Array(++c - n.length).join("0") + n;
        } else {
            return n;
        }
    };
    var txt_weekdays = ["Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"];
    var txt_ordin = {1:"st", 2:"nd", 3:"rd", 21:"st", 22:"nd", 23:"rd", 31:"st"};
    var txt_months = ["", "January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"];
    var f = {
        // Day
        d: function(){return pad(f.j(), 2)},
        D: function(){return f.l().substr(0,3)},
        j: function(){return jsdate.getDate()},
        l: function(){return txt_weekdays[f.w()]},
        N: function(){return f.w() + 1},
        S: function(){return txt_ordin[f.j()] "/1/1")) / 864e5 0},
     
        // Week
        W: function(){
            var a = f.z(), b = 364 + f.L() - a;
            var nd2, nd = (new Date(jsdate.getFullYear() + "/1/1").getDay() || 7) - 1;
            if(b <= 2 && ((jsdate.getDay() || 7) - 1) <= 2 - b){
                return 1;
            } else{
                if(a <= 2 && nd >= 4 && a >= (6 - nd)){
                    nd2 = new Date(jsdate.getFullYear() - 1 + "/12/31");
                    return date("W", Math.round(nd2.getTime()/1000));
                } else{
                    return (1 + (nd <= 3 "").slice(2)},
     
        // Time
        a: function(){return jsdate.getHours() > 11 "pm" : "am"},
        A: function(){return f.a().toUpperCase()},
        B: function(){
            // peter paul koch:
            var off = (jsdate.getTimezoneOffset() + 60)*60;
            var theSeconds = (jsdate.getHours() * 3600) + (jsdate.getMinutes() * 60) + jsdate.getSeconds() + off;
            var beat = Math.floor(theSeconds/86.4);
            if (beat > 1000) beat -= 1000;
            if (beat < 0) beat += 1000;
            if ((String(beat)).length == 1) beat = "00"+beat;
            if ((String(beat)).length == 2) beat = "0"+beat;
            return beat;
        },
        g: function(){return jsdate.getHours() % 12 || 12},
        G: function(){return jsdate.getHours()},
        h: function(){return pad(f.g(), 2)},
        H: function(){return pad(jsdate.getHours(), 2)},
        i: function(){return pad(jsdate.getMinutes(), 2)},
        s: function(){return pad(jsdate.getSeconds(), 2)},
        //u not supported yet
     
        // Timezone
        //e not supported yet
        //I not supported yet
        O: function(){
            var t = pad(Math.abs(jsdate.getTimezoneOffset()/60*100), 4);
            if (jsdate.getTimezoneOffset() > 0) t = "-" + t; else t = "+" + t;
            return t;
        },
        P: function(){var O = f.O();return (O.substr(0, 3) + ":" + O.substr(3, 2))},
        //T not supported yet
        //Z not supported yet
     
        // Full Date/Time
        c: function(){return f.Y() + "-" + f.m() + "-" + f.d() + "T" + f.h() + ":" + f.i() + ":" + f.s() + f.P()},
        //r not supported yet
        U: function(){return Math.round(jsdate.getTime()/1000)}
    };
     
    return format.replace(/[\\]?([a-zA-Z])/g, function(t, s){
        if( t!=s ){
            // escaped
            ret = s;
        } else if( f[s] ){
            // a date function exists
            ret = f[s]();
        } else{
            // nothing special
            ret = s;
        }
        return ret;
    });
}

//test
alert(date('Y-m-d H:i:s',(new Date).getTime()/1000));
alert(date('Y-m-d',(new Date).getTime()/1000));
alert(date('Y-m-d H:i:s','1355252653'));