例子，js 计算日期相隔天数。
代码：
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>
<script language=javascript>
//判断年份是否是闰年
function isLeapYear(year){
if(year % 4 == 0 && ((year % 100 != 0) || (year % 400 == 0)))
{
return true;
}
return false;
}
//判断前后两个日期
function validatePeriod(fyear,fmonth,fday,byear,bmonth,bday){
if(fyear < byear){
return true;
}else if(fyear == byear){
if(fmonth < bmonth){
return true;
} else if (fmonth == bmonth){
if(fday <= bday){
return true;
}else {
return false;
}
} else {
return false;
}
}else {
return false;
}
}
//计算两个日期的差值
function get()
{
var d1 = document.getElementById("id1").value;
var d2 = document.getElementById("id2").value;
var disNum=compareDate(d1,d2);
alert(disNum);
}
function compareDate(date1,date2)
{
var regexp=/^(d{1,4})[-|.]{1}(d{1,2})[-|.]{1}(d{1,2})$/;
var monthDays=[0,3,0,1,0,1,0,0,1,0,0,1];
regexp.test(date1);
var date1Year=RegExp.$1;
var date1Month=RegExp.$2;
var date1Day=RegExp.$3;
regexp.test(date2);
var date2Year=RegExp.$1;
var date2Month=RegExp.$2;
var date2Day=RegExp.$3;
if(validatePeriod(date1Year,date1Month,date1Day,date2Year,date2Month,date2Day)){
firstDate=new Date(date1Year,date1Month,date1Day);
secondDate=new Date(date2Year,date2Month,date2Day);
result=Math.floor((secondDate.getTime()-firstDate.getTime())/(1000*3600*24));
for(j=date1Year;j<=date2Year;j++){
if(isLeapYear(j)){
monthDays[1]=2;
}else{
monthDays[1]=3;
}
for(i=date1Month-1;i<date2Month;i++){
result=result-monthDays[i];
}
}
return result;
}else{
return 'the first field must before the second date.';
}
}
</script>
</head>
<body>
<input type=text value="2008-02-04" id=id1>
<input type=text value="2008-03-04" id = id2>
<input type=button id=bt value="OK" onclick="get()">
</body>
</html>