간단하고 알기 쉬운 js 날짜 포맷 함수

<script type="text/javascript">
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 ddd = new Date();
document.write (ddd.format('yyyy-MM-dd hh:mm:ss'));
</script>