Date.prototype.Format = function(formatStr)   
{   
    var str = formatStr;   
    //var Week = ['日','一','二','三','四','五','六'];  
    str=str.replace(/yyyy|YYYY/,this.getFullYear());   
    //str=str.replace(/yy|YY/,(this.getYear() % 100)>9?(this.getYear() % 100).toString():'0' + (this.getYear() % 100));   
    str=str.replace(/MM|mm/,this.getMonth()>8?(this.getMonth()+1).toString():'0' + (this.getMonth()+1));   
    //str=str.replace(/M/g,this.getMonth());   
    //str=str.replace(/w|W/g,Week[this.getDay()]);   
    str=str.replace(/dd|DD/,this.getDate()>9?this.getDate().toString():'0' + this.getDate());   
    //str=str.replace(/d|D/g,this.getDate());   
    //str=str.replace(/hh|HH/,this.getHours()>9?this.getHours().toString():'0' + this.getHours());   
    //str=str.replace(/h|H/g,this.getHours());   
   // str=str.replace(/mm/,this.getMinutes()>9?this.getMinutes().toString():'0' + this.getMinutes());   
    //str=str.replace(/m/g,this.getMinutes());   
    //str=str.replace(/ss|SS/,this.getSeconds()>9?this.getSeconds().toString():'0' + this.getSeconds());   
    //str=str.replace(/s|S/g,this.getSeconds());   
    return str;   
}   
var myDate = new Date();
var nowDate=myDate.Format("yyyy-mm-dd");

//计算天数差的函数，通用
  function DateDiff(sDate1, sDate2){  //sDate1和sDate2是2002-12-18格式
    var aDate, oDate1, oDate2, iDays
    aDate = sDate1.split("-")
    oDate1 = new Date(aDate[1] + '-' + aDate[2] + '-' + aDate[0])  //转换为12-18-2002格式
    aDate = sDate2.split("-")
    oDate2 = new Date(aDate[1] + '-' + aDate[2] + '-' + aDate[0])
    //alert(oDate1 - oDate2)
    iDays = parseInt(Math.abs(oDate1 - oDate2) / 1000 / 60 / 60 /24)  //把相差的毫秒数转换为天数
    return iDays
  }