javascript时间函数

<script language="javascript" type="text/javascript">//日期转换为字符串"yyyy-mm-dd hh:mm:ss"Date.prototype.toCommonCase=function(){ var xYear=this.getYear(); xYear=xYear+1900; var xMonth=this.getMonth()+1; if(xMonth<10){ xMonth="0"+xMonth; } var xDay=this.getDate(); if(xDay<10){ xDay="0"+xDay; }var xHours=this.getHours(); if(xHours<10){ xHours="0"+xHours; }var xMinutes=this.getMinutes(); if(xMinutes<10){ xMinutes="0"+xMinutes; }var xSeconds=this.getSeconds(); if(xSeconds<10){ xSeconds="0"+xSeconds; } return xYear+"-"+xMonth+"-"+xDay+" "+xHours+":"+xMinutes+":"+xSeconds; }//字符串转日期function strToDate(str){                var strDate = str.substring(0, 9);                var strTime = str.substring(11, 20);                var Dates = strDate.split('-');                var Times = strTime.split(':');                myDate = new Date();                myDate.setFullYear(Dates[0]);                myDate.setMonth(Dates[1]);                myDate.setDate(Dates[2]);                myDate.setHours(Times[0]);                myDate.setMinutes(Times[1]);                myDate.setSeconds(Times[2]);                return myDate;}//增加天数function AddDays(year , month , date , DaysToAdd) {    var srcdate=new Date();    srcdate.setFullYear(year);    srcdate.setMonth(month);    srcdate.setDate(date+DaysToAdd);    return srcdate.toCommonCase();}function limit3206Date(days,starttime){    // 计算当前日期 + 限制日期 =最多可选时间    //WdatePicker({dateFmt:"yyyy-MM-dd HH-mm-ss"});    var mintime = strToDate(starttime);    var maxtime = AddDays(mintime.getYear(), mintime.getMonth(), mintime.getDate() , days);}var time = new Date();var maxtime = AddDays(time.getFullYear(), 10, 18 , 30);        alert(maxtime);</script>