Date.prototype.Format = function (fmt) { //author: meizz
  var o = {
    "M+": this.getMonth() + 1, //月份
    "d+": this.getDate(), //日
    "h+": this.getHours(), //小时
    "m+": this.getMinutes(), //分
    "s+": this.getSeconds(), //秒
    "q+": Math.floor((this.getMonth() + 3) / 3), //季度
    "S": this.getMilliseconds() //毫秒
  };
  if (/(y+)/.test(fmt)) fmt = fmt.replace(RegExp.$1, (this.getFullYear() + "").substr(4 - RegExp.$1.length));
  for (var k in o)
  if (new RegExp("(" + k + ")").test(fmt)) fmt = fmt.replace(RegExp.$1, (RegExp.$1.length == 1) "00" + o[k]).substr(("" + o[k]).length)));
  return fmt;
}

<SCRIPT LANGUAGE="JavaScript">
<!--
var myDate = new Date();
  myDate.getYear();    //获取当前年份(2位)
  myDate.getFullYear();  //获取完整的年份(4位,1970-"23:30:00")
{
alert(mytime);
}
//-->
</SCRIPT>