Parse and format time in JavaScript.

convert_time.js

// Parse and format time.
// Written by physacco. 2011-05-13.
//
// Tested on:
// - Mozilla SpiderMonkey JavaScript-C 1.7.0 2007-10-03.
// - Mozilla Rhino 1.7 release 0.7.r2.fc12 2009 07 28.
//
// To run it with nodejs, substitute print with console.log.

// YYYY-mm-dd HH:MM:SS
function parseUTCDate(str) {
    var re = /^(\d{4})-(\d{2})-(\d{2}) (\d{2}):(\d{2}):(\d{2})$/;
    var md = re.exec(str);
    if(md) {
        var year   = parseInt(md[1]);
        var month  = parseInt(md[2]) - 1;
        var date   = parseInt(md[3]);
        var hour   = parseInt(md[4]);
        var minute = parseInt(md[5]);
        var second = parseInt(md[6]);

        var dt = new Date();
        dt.setUTCFullYear(year);
        dt.setUTCMonth(month);
        dt.setUTCDate(date);
        dt.setUTCHours(hour);
        dt.setUTCMinutes(minute);
        dt.setUTCSeconds(second);
        return dt;
    }
    else {
        return null;
    }
}

// dateobj: a Date object
function formatDateLocale(dateobj) {
    var year   = dateobj.getFullYear();
    var month  = dateobj.getMonth() + 1;
    var date   = dateobj.getDate();
    var hour   = dateobj.getHours();
    var minute = dateobj.getMinutes();
    var second = dateobj.getSeconds();

    var YY = year;
    var mm = month < 10 ? '0' + month : month;
    var dd = date < 10 ? '0' + date : date;
    var HH = hour < 10 ? '0' + hour : hour;
    var MM = minute < 10 ? '0' + minute : minute;
    var SS = second < 10 ? '0' + second : second;

    return YY+'-'+mm+'-'+dd+' '+HH+':'+MM+':'+SS;
}

var utc_str = "2011-05-13 13:56:34";
var date = parseUTCDate(utc_str);
print(date);  // or console.log on nodejs

var locale_str = formatDateLocale(date);
print(locale_str);  // or console.log on nodejs

// Output:
// Fri May 13 2011 21:56:34 GMT+0800 (CST)
// 2011-05-13 21:56:34