js日期计算

方法一：

/+--------------------------------------------------- 
//| 求两个时间的天数差 日期格式为 YYYY-MM-dd  
//+--------------------------------------------------- 
function daysBetween(DateOne,DateTwo) 
{  
    var OneMonth = DateOne.substring(5,DateOne.lastIndexOf ('-')); 
    var OneDay = DateOne.substring(DateOne.length,DateOne.lastIndexOf ('-')+1); 
    var OneYear = DateOne.substring(0,DateOne.indexOf ('-')); 
 
    var TwoMonth = DateTwo.substring(5,DateTwo.lastIndexOf ('-')); 
    var TwoDay = DateTwo.substring(DateTwo.length,DateTwo.lastIndexOf ('-')+1); 
    var TwoYear = DateTwo.substring(0,DateTwo.indexOf ('-')); 
 
    var cha=((Date.parse(OneMonth+'/'+OneDay+'/'+OneYear)- Date.parse(TwoMonth+'/'+TwoDay+'/'+TwoYear))/86400000);  
    return Math.abs(cha); 
} 

方法二：

function  btnCount_Click(){  
       s1  =  "2006-12-18"  
       s2  =  "2007-1-5"  
       alert("第一个日期；"+s1+"/n第二个日期："+s2+"/n相差"+DateDiff(s1,s2)+"天")  
   }  

   //计算天数差的函数，通用  
   function  DateDiff(sDate1,  sDate2){    //sDate1和sDate2是2006-12-18格式  
       var  aDate,  oDate1,  oDate2,  iDays  
       aDate  =  sDate1.split("-")  
       oDate1  =  new  Date(aDate[1]  +  '-'  +  aDate[2]  +  '-'  +  aDate[0])    //转换为12-18-2006格式  
       aDate  =  sDate2.split("-")  
       oDate2  =  new  Date(aDate[1]  +  '-'  +  aDate[2]  +  '-'  +  aDate[0])  
       iDays  =  parseInt(Math.abs(oDate1  -  oDate2)  /  1000  /  60  /  60  /24)    //把相差的毫秒数转换为天数  
       return  iDays  
   }