JS日期:根据出生日期 得到周岁年龄

//JS日期系列：根据出生日期 得到周岁年龄
//参数strBirthday已经是正确格式的2007.02.09这样的日期字符串
//后续再增加相关的如日期判断等JS关于日期处理的相关方法
function jsGetAge(strBirthday)
{
var returnAge;
var strBirthdayArr=strBirthday.split(".");
var birthYear = strBirthdayArr[0];
var birthMonth = strBirthdayArr[1];
var birthDay = strBirthdayArr[2];

d = new Date();
var nowYear = d.getYear();
var nowMonth = d.getMonth() + 1;
var nowDay = d.getDate();

if(nowYear == birthYear)
{
returnAge = 0;//同年 则为0岁
}
else
{
var ageDiff = nowYear - birthYear ; //年之差
if(ageDiff > 0)
{
if(nowMonth == birthMonth)
{
var dayDiff = nowDay - birthDay;//日之差
if(dayDiff < 0)
{
returnAge = ageDiff - 1;
}
else
{
returnAge = ageDiff ;
}
}
else
{
var monthDiff = nowMonth - birthMonth;//月之差
if(monthDiff < 0)
{
returnAge = ageDiff - 1;
}
else
{
returnAge = ageDiff ;
}
}
}
else
{
returnAge = -1;//返回-1 表示出生日期输入错误 晚于今天
}
}

return returnAge;//返回周岁年龄

}