简单的两行javascript代码就能按指定格式输出日期和时间

function date2str(x,y) {
    var z = {
		y:x.getFullYear(),
		M:x.getMonth()+1,
		d:x.getDate(),
		h:x.getHours(),
		m:x.getMinutes(),
		s:x.getSeconds()
	};
    return y.replace(/(y+|M+|d+|h+|m+|s+)/g, 
		function(v) {
			return ((v.length>1?"0":"")+z[v.slice(-1)]).slice(-(v.length>2?v.length:2))
		}
	);
}
document.write("<p>" + date2str(new Date(),"yy-M-d h:m:s") + "</p>");
document.write("<p>" + date2str(new Date(),"yyyy/M/dd hh:mm:ss") + "</p>");