本文实例讲述了JS根据生日算年龄的方法。分享给大家供大家参考。具体实现方法如下：

function parseDate(str){

if(str.match(/^d{4}[-/s+]d{1,2}[-/s+]d{1,2}$/)){

return new Date(str.replace(/[-/s+]/i,'/'));

}

else if(str.match(/^d{8}$/)){

return new Date(str.substring(0,4)+'/'+str.substring(4,6)+'/'+str.substring(6));

}

else{

return ('时间转换发生错误！');

}

}

function GetAgeByBrithday(birthday){

var age=-1;

var today=new Date();

var todayYear=today.getFullYear();

var todayMonth=today.getMonth()+1;

var todayDay=today.getDate();

var birthday=parseDate(birthday);

if(parseDate(birthday)!='时间转换发生错误！')

{

birthdayYear=birthday.getFullYear();

birthdayMonth=birthday.getMonth();

birthdayDay=birthday.getDate();

if(todayYear-birthdayYear<0)

{

alert("出生日期选择错误!");

}

else

{

if(todayMonth*1-birthdayMonth*1<0)

{

age = (todayYear*1-birthdayYear*1)-1;

}

else

{

if(todayDay-birthdayDay>=0)

{//alert(thisDay+'-'+brithd+"_ddd");

age = (todayYear*1-birthdayYear*1);

}

else

{

age = (todayYear*1-birthdayYear*1)-1;

}

}

}

return age*1;

}

else

{

return -1;

}

}

希望本文所述对大家的javascript程序设计有所帮助。