js 计算月份差 ,天数差

<SCRIPT language="javascript">

//计算月份差
  function getMonthNumber(date1,date2){
  //默认格式为"20030303",根据自己需要改格式和方法
  var year1 =  date1.substr(0,4);
  var year2 =  date2.substr(0,4);
  var month1 = date1.substr(4,2);
  var month2 = date2.substr(4,2);
  
  var len=(year2-year1)*12+(month2-month1);
  
  return len;

 }

var len=getMonthNumber('200403','200504');

//alert('2003-03-03'.replace(/-/g, "/"));

//alert('2003-03-03'.replace(/-/g, ""));

if(len<0){
  alert("查询起始月份不能比查询终止月份大.");
 }else if(len >11){  
   alert("查询月份时间段不能超过12个月.");

 }

</SCRIPT>

<SCRIPT language="javascript">

//计算天数差
  function getDayNumber(date1,date2){
  //默认格式为"20030303",根据自己需要改格式和方法
  var year1 =  date1.substr(0,4);
  var year2 =  date2.substr(0,4);
  var month1 = date1.substr(4,2);
  var month2 = date2.substr(4,2);
  
  var day1 = date1.substr(6,2);
  var day2 = date2.substr(6,2);
  
  temp1 = year1+"/"+month1+"/"+day1;
  temp2 = year2+"/"+month2+"/"+day2;
  
  var dateaa= new Date(temp1);
  var datebb = new Date(temp2);
  var date = datebb.getTime() - dateaa.getTime();
  var time = Math.floor(date / (1000 * 60 * 60 * 24));
  alert(time);

 }

getDayNumber('20030303','20040503');

</SCRIPT>