格式化日期串兼容ie8以下
http://www.webdeveloper.com/forum/showthread.php?t=247673

function formatDate(date){    var h = date.getHours();    var n = date.getMinutes();    return (h < 10 ? '0' + h : h) + ':' + (n < 10 ? '0' + n : n);}function formatDateStr(dateStr){    var d = new Date(dateStr);    if(isNaN(d)){        var rx = /^(\d{4}\-\d\d\-\d\d([tT][\d:\.]*)?)([zZ]|([+\-])(\d\d):(\d\d))?$/;        var p = rx.exec(dateStr) || [];        if(p[1]){            var day= p[1].split(/\D/);            for(var i=0,L=day.length;i<L;i++){              day[i] = parseInt(day[i], 10) || 0;            };            day[1] -= 1;            day = new Date(Date.UTC.apply(Date, day));            if(!day.getDate()) return NaN;            if(p[5]){                var tz = (parseInt(p[5], 10)*60);                if(p[6]) tz += parseInt(p[6], 10);                if(p[4] == '+') tz *= -1;                if(tz) day.setUTCMinutes(day.getUTCMinutes() + tz);            }            return formatDate(day);        }        return NaN;    }    return formatDate(d);}