js 计算天数差

 function storeDate(libDateStr){
      var nowDate = new Date();
   var libDate = new Date(libDateStr.substr(0,10));
   var iDays = parseInt(Math.abs(libDate - nowDate ) / 1000 / 60 / 60 /24)//把相差的毫秒数转换为天数 
    }