JavaScript implements time format output FormatDate function_javascript skills

Date.prototype.Format = function(fmt) { //author: meizz 
If (this == "Invalid Date") {
        return "";
}  
var o = {
"M " : this.getMonth() 1, //month
"d": this.getDate(), //Day
"H ": this.getHours(), //hours
"m ": this.getMinutes(), //Minutes
"s": this.getSeconds(), //seconds
" q " : Math.floor((this.getMonth() 3) / 3), //Quarter " 🎜> "S" : this.getMilliseconds()
//milliseconds
};
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) ? (o[k])
: (("00" o[k]).substr(("" o[k]).length)));
Return fmt;
}